ELECTRONIC CONFIGURATION OF ELEMENTS

Energy Levels in Many-Electron Atoms

In order to fill the electrons in various atomic orbitals, we need to know how the energy levels vary as the nuclear charge increases. For hydrogen-like atoms (single electron in the outer shell), the approximate energy levels are as indicated below:

Energy levels of H-like atoms :::::: : ::: ::::: ::::::: 4s4p4d4f - --- ----- ------- 3s3p3d - --- ----- 2s2p - --- (a large gap) 1s -

The shielding effect and electron-electron interactions cause the energy levels of subshells such as 2s & 2p to be different from those of H-like atoms. This is done by treating the electron shield cores as a proton but the core has an effective nuclear charge Z.

For the H-like atoms, energy levels for 2s, 2p stay the same, but the separation between 2s and 2p energy levels increases as the atomic number (Z) increases.

Similar situations happen for 3s, 3p, and 3d energy levels. The energy diagrams of H, Li & K are used to illustrate this point. The color diagram is from a Hyperion website discussing quantum numbers and structure of atoms.

Variation of energy levels for atomic orbitals of some elements H

_2s_ _ _2p

_ 1s

Li

_ _ _ 2p _ 2s

_ 1s

Be

_ _ _ 2p

_ 2s

_ 1s

B

_ _ _ 2p

_ 2s

_ 1s

C

_ _ _ 2p

_ 2s

_ 1s

N

_ _ _ 2p

_ 2s

_ 1s

O

_ _ _ 2p

_ 2s

_ 1s

F

_ _ _ 2p

_ 2s

_ 1s

Understand how the energy level vary is the key to the Aufbau process, because Electrons tend to occupy the lowest energy level available. But before we talk about the Aufbau process, we need to be aware of the Pauli exclusion principle and the Hund's rule.

The Pauli Exclusion Principle

The Pauli exclusion principle suggests that only two electrons with opposite spin can occupy an atomic orbital. Stated another way, no two electrons have the same 4 quantum numbers n, l, m, s. Pauli's exclusion principle can be stated in some other

ways, but the idea is that energy states have limit room to accommodate electrons. A state accepts two electrons of different spins.

In applying this rule, you should realize that an atomic orbital is an energy state.

Hund's RULE

Hund's rule suggests that electrons prefer parallel spins in separate orbitals of subshells. This rule guides us in assigning electrons to different states in each sub-shell of the atmic orbitals. In other words, electrons fill each and all orbitals in the subshell before they pair up with opposite spins.

Pauli exclusion principle and Hund's rule guide us in the aufbau process, which is figuring out the electron configurations for all elements.

The Aufbau Procedure

The aufbau procedure (filling order of atomic orbitals) is used to work out the electron confiturations of all atoms. However, modification should be made by applying Hund's rule to be discussed in the next section. The aufbau procedure is based on a rough energy levels diagram of many-electron atoms as shown below: 7s |~ 5d |----- 5f |_______ Actanides 6s |_ 6p |~~~ 5d |===== 4f |======= Lanthanides 5s |_ 5p |~~~ 4d |----- Note the trend 5s 4d 5p & develope a pattern 4s |_ 4p |~~~ 3d |----- Transition elements 3s |_ 3p |--- 2s |_ 2p |--- 1s |-

The fine difference between energy levels cannot be adquately shown.

You've learned various techniques to work out the electronic configurations of elements. Here is yet another form of an energy level diagram:

7p _ _ _ 7s _ 5f - - - - - - - 6d ~ ~ ~ ~ ~ 6p _ _ _ 6s _ 4f - - - - - - - 5d ~ ~ ~ ~ ~ 5s _ 4d - - - - - 5p ~ ~ ~ 4s _ 3d - - - - - 4p ~ ~ ~ 3s _ 3p - - - 2s _ 2p - - - 1s _

In order to master the technique of the aufbau procedure, you should apply the Hund's rule and Pauli exclusion principle to work out the electronic configuration for closed shells of inert gases. After you worked out, you may compare your result with the following. Do not try to remember it, it is important to know how to work it out.

Z= 2 10 1 36 4 1s2 2s22p6 3s23p6 4s23d104p6 5s24d105p6 6s24f145d106p6

8 5 86

He Ne Ar Kr Xe Rn

Block of elements by highest occupied atomic orbitals

The highest atomic orbitals occupied by electrons determine the properties of the elements. According to this scheme, the periodic table can be divided into s, p, d, and f blocks as seen in the table on the right.

This table shows the filling order of atomic orbitals as

Block of elements by last filled atomic orbitals

1s 2s 3s 4s 5s 6s 7s

4f - - - - - 4f 5f - - - - - 5f

3d - - - 3d 4d - - - 4d 5d - - - 5d 6d - - - 6d

2p - 2p 3p - 3p 4p - 4p 5p - 5p 6p - 6p 7p - 7p 1s

2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

The s- and p-blocks of elements are called main group elements. The d-block elements are called transition elements The f-block elements are called the inner transition elements.

In an ordinary periodic table, the s, p, and d block elements are in the main body of the Periodic Table, whereas the f block elements are placed below the main body. If we placed them on the same period where they belong, the Periodic Table would be too long for the screen to accommodate. Thus, we keep the Periodic Table in the usual (long) form.

Special Electronic Configurations When two electrons occupy the same orbital, they not only have different spins (Pauli exclusion principle), the pairing raises the energy slightly. On the other hand, a half filled subshell and a full filled subshell lower the energy, gaining some stability. Bearing this in mind, you will be able to understand that the above rules are not obeyed exactly in heavier atoms.

CHEMICAL ELEMENTS AND THEIR SYMBOLS

ELEMENT SYMBOL ELEMENT SYMBOL

actinium Ac mendelivium Md

aluminium Al mercury Hg

americium Am molybdenum Mo

antimony Sb neodymium Nd

argon Ar neon Ne

arsenic As neptunium Np

astatine At nickel Ni

barium Ba niobium Nb

berkelium Bk nitrogen N

beryllium Be nobelium No

bismuth Bi osmium Os

boron B oxygen O

bromine Br palladium Pd

cadmium Cd phosphorus P

caesium Cs platinum Pt

calcium Ca plutonium Pu

californium Cf polonium Po

carbon C potassium K

cerium Ce praseodymium Pr

chlorine Cl promethium Pm

chromium Cr protactinium Pa

cobalt Co radium Ra

copper Cu radon Rn

curium Cm rhenium Re

dysprosium Dy rhodium Rh

einsteinium Es rubidium Rb

erbium Er ruthenium Ru

europium Eu rutherfordium Rf

fermium Fm samarium Sm

fluorine F scandium Sc

francium Fr selenium Se

gadolinium Gd silicon Si

gallium Ga silver Ag

germanium Ge sodium Na

gold Au strontium Sr

hafnium Hf sulphur S

hahnium Ha tantalum Ta

helium He technetium Tc

holmium Ho tellurium Te

hydrogen H terbium Tb

indium In thallium Tl

iodine I thorium Th

iridium Ir thulium Tm

iron Fe tin Sn

krypton Kr titanium Ti

kurchatovium Ku tungsten W

lanthanum La uranium U

lawrencium Lr vanadium V

lead Pb xenon Xe

lithium Li ytterbium Yb

lutetium Lu yttrium Y

magnesium Mg zinc Zn

manganese Mn zirconium Zr

GRAPHING WITH EXCEL

Introduction

Excel is a type of computer program also called spreadsheet. It is probably the most widely used program for the management and analysis of numeric data. The utility of Excel and other spreadsheet programs comes from its visual method of storing and management of data. Each unique bit of data is held in a cell. Each cell has a unique location and can be referenced to format the display of the numeric data, create graphs, and perform mathematical operations on the data.

N.B. This knowledge will aid us to graphically follow the trends in the properties of the elements across the periodic table.

Inputting data

You can enter data by simply clicking on one of the cells in the spreadsheet and typing in your values. Normally you will start entering somewhere near the upper left corner of the spreadsheet. You can move to the next cell in a number of ways:

• Clicking on the next cell you want to enter data into • Return will move to the next cell down • Tab will move to the next cell to the right • Arrow keys will move in the direction of the arrow

Referring to the figure below, the first row of data might be entered:

1 Tab 52 Tab 48 Tab 73.5

The first column might be entered:

1 Return 3 Return 2 Return 5 Return 2

Identifying cells

Each cell is located in a rectilinear grid of cells and is located by a column and row designation. Columns are designated by letters while rows are designated by numbers.

Cell ranges; Groups of cells can also be specified by placing a colon between the upper left and lower right corners of the group of cells. For example (Figure 1):

Figure 1

This highlighted column of cells would be B1:B5. Notice that the letter designation is the same for a single column of cells. Another selection might be (Figure 2):

Figure 2

Here, multiple rows and columns are selected and would be designated as A2:C4.

Entering and Formatting the Data in Excel

Open Excel and begin by formatting the spreadsheet cells so the appropriate number of decimal places are displayed (see Figure 1a).

• Click and drag over the range of cells that will hold the concentration data (A5 through A10 for the sample data)

• Choose Format > Cells... (this is shorthand for choosing Cells... from the Format menu at the top of the Excel window)

• Click on the Number tab • Under Category choose Number and set Decimal places to 5 • Click OK • Repeat for the absorbance data column (B5 through B10 for the

sample data), setting the decimal places to 4

Your data will go in the first two columns in the spreadsheet. We want to show Beer-lambarts law. Type any values the appropriate cells to represent Column A concentration and Column B Absorbance (For example follow the steps below illustrated in Figure 3a).

• Title the spreadsheet page in cell A1 • Label Column A as the Concentration (M) of the known

solutions in cell A3. This is the independent variable • Label Column B as the Absorbance readings for each of the

solutions in cell B3. This is the dependent variable • Enter the independent and dependent variable values • Finally, enter the information shown in rows 12 and 13. These are

absorbance values from two samples of unknown concentrations (more on this later).

Figure 3a

Creating the Initial Scatter Plot

With the data you want graphed highlighted, start the chart wizard

• Choose the Chart Wizard icon from the tool bar (see Figure 3b for two examples). If the Chart Wizard is not visible, you can also choose Insert > Chart...

Figure 3b.

The first dialogue of the wizard comes up

Choose XY (Scatter) and the unconnected points icon for the Chart sub-type (Figure 4)

Figure 4.

• Click Next >

The Data Range box should reflect the data you highlighted in the spreadsheet. The Series option should be set to Columns, which is how your data is organized (see Figure 5).

Figure 5.

• Click Next >

The next dialogue in the wizard is where you label your chart (Figure 6)

• Enter Beer's Law for the Chart Title • Enter Concentration (M) for the Value X Axis • Enter Absorbance for the Value Y Axis

Figure 6.

• Click on the Legend tab • Click off the Show Legend option (Figure 7)

Figure 7.

• Click Next >

Keep the chart as object in Sheet 1 (the current sheet). See Figure 4e.

• Click Finish

NOTE: You can try to apply this graphing to the variation of melting points (vertical axis – Y) against the atomic numbers (horizontal axis – X).

Atomic Size The first of these properties is the atomic size. You know that each atom has a nucleus inside and electrons zooming around outside the nucleus. It should seem reasonable that the size of an atom depends on how far away its outermost (valence) electrons are from the nucleus. If they are very close to the nucleus, the atom will be very small. If they are far away, the atom will be quite a bit larger. So the atomic size is determined by how much space the electrons take up.

Measuring the size of atoms is, in some ways, like measuring the size of cotton balls or automobile tires. The value you get depends on the conditions under which they are measured. A "free" cotton ball has a different size than when it is in the package. The radius of the tire is different when measured to the top of the tire than when measured to the bottom of the tire resting on the ground. Different values for the sizes of atoms are obtained depending on both the method used and the conditions in which the atoms find itself - free or bonded to other atoms. The following table gives a variety of values collected from a variety of sources.Whichever set of values you choose to use, note the trends.

Atomic Sizes (in Angstroms, which is 10-10 meter) from Various Sources

1.58 0.3 1.2

0.98 n.a.

4.10 1.52

2.80 1.12

2.34 0.88

1.82 0.77

1.50 0.70 1.5

1.30 0.66 1.40

1.14 0.64 1.35

1.02 n.a. 1.60

4.46 1.86

3.44 1.60

3.64 1.43

2.92 1.17

2.46 1.10 1.9

2.18 1.04 1.85

1.94 0.99 1.80

1.76 n.a. 1.92

5.54 2.31

4.46 1.97

4.18 1.60

4.00 1.46

3.84 1.31

3.70 1.25

3.58 1.29

3.44 1.26

3.34 1.25

3.24 1.24

3.14 1.28

3.06 1.33

3.62 1.22

3.04 1.22

2.66 1.21 2.0

2.44 1.17 2.00

2.24 1.14 1.95

2.06 n.a. 1.97

5.96 2.44

4.90 2.15

4.54 1.80

4.32 1.57

4.16 1.41

4.02 1.36

3.90 1.3

3.78 1.33

3.66 1.34

3.58 1.38

3.50 1.44

3.42 1.49

4.00 1.62

3.44 1.4

3.06 1.41 2.2

2.84 1.37 2.20

2.64 1.33 2.15

2.48 n.a. 2.17

6.68 2.62

5.56 2.17

5.48 1.88

4.32 1.57

4.18 1.43

4.04 1.37

3.94 1.37

3.84 1.34

3.74 1.35

3.66 1.38

3.58 1.44

3.52 1.52

4.16 1.71

3.62 1.75

3.26 1.46

3.06 1.4

2.86 1.4

2.68 n.a.

2.7

2.20

2.2

Atomic diameter computed using quantum mechanical calculations, Periodic Chart of the

Atoms (1979), Sargent-Welch Atomic radii and covalent radii, "Chemical Systems," Chemical Bond Approach Project (1964), McGraw-Hill Van der Waals radii, Handbook of Chemistry and Physics, 65th Ed. (1984), CRC Press and "Chemical Systems"

Let's make some comparisons in a family and in a period. In a family--like from hydrogen to lithium to sodium on down--the atomic size increases. As you go down a group, the size increases. As you go across a period, as from lithium to neon, notice that the size decreases. You need to remember (or memorize) those trends.

Now let's talk about why that's the case and relate it back to the various factors presented earlier. Remember that the nuclear charge and the shielding electrons combine to make the effective nuclear charge. That is a very important factor when you are comparing elements in a period. As you go across a period, the nuclear charge increases and the number of energy levels stays the same. Consequently, the number of shielding electrons stays the same and the effective nuclear charge increases. As the effective nuclear charge increases, it pulls the electrons in closer and closer to the nucleus. So as you go across a period, the increase in the nuclear charge causes a decrease in the atomic size because the electrons in the valence energy level are pulled in closer and closer.

Now let's make comparison within a family such as hydrogen down to francium (Fr). It is true that the nuclear charge is increasing, but so is the number of shielding electrons. The number of shielding electrons increases by the same amount that the nuclear charge increases. So the effective nuclear charge felt by the valence electrons stays the same. There is no increase in the effective nuclear charge but there is an increase in the number of energy levels that are being used. Consequently, the electrons in the valence energy level are further and further away from the nucleus because they are in higher energy levels. Consequently, the important factor in a vertical comparison on the periodic table is the number of energy levels that are being used because the increase in the number of shielding electrons cancels out the increase in the nuclear charge.

To summarize, as you go across a period, the increase in the nuclear charge is the most important factor because the number of energy levels stays the same. As you go down a group, the increase in shielding electrons more or less cancels out the increase in nuclear charge, leaving the increase in the number of energy levels as the most important factor. This is true not only for atomic size but for other properties as well.

If you have a sharp eye and a good memory, you may have noticed that the trend shown here as you go from lithium through neon is slightly different than what was shown in the diagram of Lothar Meyer's atomic volumes. The reason for this is something that we will be getting into a little bit later in the course. It has to do with the way that atoms attract to one another. The amount of space taken up by a collection of atoms depends not only on the amount of space taken up by the individual atoms, but also on how much they compact when they combine with one another. In Meyer's diagram, there is first a decrease in volume as you go across the table and then an increase; whereas in this

diagram, there is a decrease all the way across. Meyer was measuring two factors. One was the size of the individual atoms and the second was the compressibility of the atoms when they combine with more than one of themselves. In a sense, it would be like using atomic radii for the metals and an average of covalent and van der Waals radii for the nonmetals.

ATOMIC RADIUS

Measures of atomic radius

Unlike a ball, an atom doesn't have a fixed radius. The radius of an atom can only be found by measuring the distance between the nuclei of two touching atoms, and then halving that distance (= d/2).

As you can see from the diagrams, the same atom could be found to have a different radius depending on what was around it.

The left hand diagram shows bonded atoms. The atoms are pulled closely together and so the measured radius is less than if they are just touching. This is what you would get if you had metal atoms in a metallic structure, or atoms covalently bonded to each other. The type of atomic radius being measured here is called the metallic radius or the covalent radius depending on the bonding.

The right hand diagram shows what happens if the atoms are just touching. The attractive forces are much less, and the atoms are essentially "unsquashed". This measure of atomic radius is called the van der Waals radius after the weak attractions present in this situation.

IONIC RADIUS

Ions aren't the same size as the atoms they come from. Compare the sizes of sodium and chloride ions with the sizes of sodium and chlorine atoms.

Positive ions

Positive ions are smaller than the atoms they come from. Sodium is 2,8,1; Na+ is 2,8. You've lost a whole layer of electrons, and the remaining 10 electrons are being pulled in by the full force of 11 protons.

Negative ions

Negative ions are bigger than the atoms they come from. Chlorine is 2,8,7; Cl- is 2,8,8. Although the electrons are still all in the 3-level, the extra repulsion produced by the incoming electron causes the atom to expand. There are still only 17 protons, but they are now having to hold 18 electrons.

angstrom (unit of measurement) Unit of length used chiefly in measuring wavelengths of light, equal to 10−10 metre, or 0.1 nanometer. It is named for the 19th-century Swedish physicist Anders Jonas Ångström. The angstrom and multiples of it, the micron (104 Å) and the millimicron (10 Å), are also used to measure such quantities as molecular diameters and the thickness of...

Named from Ångström: Swedish physicist, a founder of spectroscopy for whom the angstrom, a unit of length equal to 10-10 metre, was named.

...whether they have 3 or 90 electrons. Approximately 50 million atoms of solid matter lined up in a row would measure 1 cm (0.4 inch). A convenient unit of length for measuring atomic sizes is the angstrom (Å), defined as 10−10 metre. The radius of an atom measures 1–2 Å. Compared with the overall size of the atom, the nucleus is even more minute. It is in...

Melting point

The melting point of a solid is the temperature range at which it changes state from solid to liquid. Although the phrase would suggest a specific temperature and is commonly and incorrectly used as such in most textbooks and literature, most crystalline compounds actually melt over a range of a few degrees or less. At the melting point the solid and liquid phase exist in equilibrium. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point. Because of the ability of some substances to supercool, the freezing point is not considered to be a characteristic property of a substance.

Boiling point

The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid. A liquid in a vacuum environment has a lower boiling point than when the liquid is at atmospheric pressure. A liquid in a high pressure environment has a higher boiling point than when the liquid is at

atmospheric pressure. In other words, the boiling point of liquids varies with and depends upon the surrounding environmental pressure.

The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, 1 atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome atmospheric pressure and lift the liquid to form bubbles inside the bulk of the liquid. The standard boiling point is now (as of 1982) defined by IUPAC as the temperature at which boiling occurs under a pressure of 1 bar.The heat of vaporization is the amount of heat required to convert or vaporize a saturated liquid (i.e., a liquid at its boiling point) into a vapor

Oxidation States, Nomenclature & Properties of elements

Oxidation state is a number assigned to an element in a compound according to some rules. This number enable us to describe oxidation-reduction reactions, and balancing redox chemical reactions. You are learning the skill to assign oxidation states (or oxidation numbers) to a variety of compounds and ions.

When an oxidation number is assigned to the element, it does not imply that the element in the compound acquires this as a charge, but rather that it is a convenient number to use for balancing chemical reactions. The guidelines for assigning oxidation states (numbers) are given below:

Rules for Assigning Oxidation Numbers

Electrochemical reactions involve the transfer of electrons. Mass and charge are conserved when balancing these reactions, but you need to know which atoms are oxidized and which atoms are reduced during the reaction. Oxidation numbers are used to keep track of how many electrons are lost or gained by each atom. These oxidation numbers are assigned using the following rules:

1. The convention is that the cation is written first in a formula, followed by the anion.

For example, in NaH, the H is H-; in HCl, the H is H+.

2. The oxidation number of a free element is always 0.

The atoms in He and N2, for example, have oxidation numbers of 0.

3. The oxidation number of a monatomic ion equals the charge of the ion.

For example, the oxidation number of Na+ is +1; the oxidation number of N3- is -3.

4. The usual oxidation number of hydrogen is +1.

The oxidation number of hydrogen is -1 in compounds containing elements that are less electronegative than hydrogen, as in CaH2.

5. The oxidation number of oxygen in compounds is usually -2.

Exceptions include OF2, since F is more electronegative than O, and BaO2, due to the structure of the peroxide ion, which is [O-O]2-.

6. The oxidation number of a Group IA element in a compound is +1. 7. The oxidation number of a Group IIA element in a compound is +2.

8. The oxidation number of a Group VIIA element in a compound is -1, except when that element is combined with one having a higher electronegativity.

The oxidation number of Cl is -1 in HCl, but the oxidation number of Cl is +1 in HOCl.

9. The sum of the oxidation numbers of all of the atoms in a neutral compound is 0.

10. The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

For example, the sum of the oxidation numbers for SO42- is -2.

Chemical Nomenclature

The following outline is to help you decide how to name a chemical compound. Use it as a flow chart to break down the different systems of naming to determine the name of a compound.

Formulas and Names of Binary Metal-Nonmetal Compounds

1. The name of the metal is first (ie: NaCl, sodium chloride) 2. The name of the nonmetal has -ide added (ie: NaCl sodium chloride) 3. IF the metal has more than one possible charge

a. With the Stock Method you must indicate which ion using the charge in roman numerals (ie: FeCl2 Iron (II) chloride).

b. Alternatively the common name may be used if the metal has more than one possible ion. Here use the Latin root and then add -ous for the lower charge. -ic for the higher charge.

i. FeCl2 ferrous chloride ii. FeCl3 ferric chloride

c. More examples showing the two different systems:

Compound Stock Method Common Name FeF2 iron (II) fluoride ferrous fluoride FeF3 iron (III)fluoride ferric fluoride Hg2Br2 mercury (I) bromide mercurous bromide HgBr2 mercury (II) bromide mercuric bromide

Formulas and Names of Binary Nonmetal-Nonmetal Compounds

1. Systematic Nomenclature: a. For names start with element to the left side on the periodic table

b. add -ide to the second element c. use Greek prefixes for number of atoms: mono, di, tri, tetra, penta, hexa,

hepta, octa, nona, deca d. Example:

i. CO carbon monoxide ii. CO2 carbon dioxide

iii. N2O5 dinitrogen pentoxide 2. Common names: -ous and -ic (-ic has greater charge, OR has fewer atoms).

Examples:

Formula Systematic Name Common Name NO nitrogen monoxide nitric oxide N2O dinitrogen monoxide nitrous oxide NO2 nitrogen dioxide nitrogen peroxide N2O5 dinitrogen pentoxide nitric anhydride N2O3 dinitrogen trioxide nitrous anhydride

Polyatomic Compounds.

1. Names of Polyatomic Ions a. Anions are negative, Cations are positive b. ammonium ion NH4

1+ c. -ide ions

i. CN1- cyanide ii. OH1- hydroxide

d. Oxyanions i. -ate ate more oxygen.

Formula Name NO2

1- nitrite NO3

1- nitrate

ii. Sometimes oxyanions have an extra hydrogen

Formula Name SO4

2- sulfate HSO4

1- hydrogen sulfate (or bisulfate)

iii. If more than two possibilities:

Formula Name ClO1- hypochlorite ClO2

1- chlorite ClO3

1- chlorate ClO4

1- perchlorate

2. Naming compounds with polyatomic ions a. Positive charge species on left (using Stock method or common name) b. Negative charge species on right (using name of polyatomic ion) c. Use parentheses as needed

Formula Ions Name BaSO4 Ba2+ and SO4

2- barium sulfate Ca(NO3)2 Ca+2 and NO3

1- calcium nitrate Ca(NO2)2 Ca+2 and NO2

1- calcium nitrite

Fe(NO3)2 Fe2+ and NO31- iron (II) nitrate or

ferrous nitrate

Acids

1. Hydro Acids: Hydro + halogen name + ic

Formula Name HCl hydrochloric acid HF hydrofluoric acid

2. OxoAcids: polyatomic ion + acid. a. Recognize as polyatomic ions with a hydrogen at the beginning of the

formula. b. Name with -ous and -ic suffix. (Works just like -ite and -ate suffix) c. -ic suffix is for acid with more oxygen atoms. d. Examples

Formula Name Source HNO3 nitric acid nitric from nitrate HNO2 nitrous acid nitrous from nitrite

Physical and Chemical Properties

All substances have properties that we can use to identify them. For example we can idenify a person by their face, their voice, height, finger prints, DNA etc.. The more of these properties that we can identify, the better we know the person. In a similar way matter has properties - and there are many of them. There are two basic types of properties that we can associate with matter. These properties are called Physical properties and Chemical properties:

Physical properties:

Properties that do not change the chemical nature of matter

Chemical properties:

Properties that do change the chemical nature of matter

Examples of physical properties are: color, smell, freezing point, boiling point, melting point, infra-red spectrum, attraction (paramagnetic) or repulsion (diamagnetic) to magnets, opacity, viscosity and density. There are many more examples. Note that measuring each of these properties will not alter the basic nature of the substance.

Examples of chemical properties are: heat of combustion, reactivity with water, PH, and electromotive force.

The more properties we can identify for a substance, the better we know the nature of that substance. These properties can then help us model the substance and thus understand how this substance will behave under various conditions.

ORES AND MINERALS

An ore is a volume of rock containing components or minerals in a mode of occurrence that renders it valuable for mining. An ore must contain materials that are

• valuable • in concentrations that can be profitably mined, transported, milled, and processed. • able to be extracted from waste rock by mineral processing techniques.

A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure and specific physical properties. A rock, by comparison, is an aggregate of minerals and need not have a specific chemical composition. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms. The study of minerals is called mineralogy.

To be classified as a true mineral, a substance must be a solid and have a crystalline structure. It must also be a naturally occurring, homogeneous substance with a defined chemical composition. Traditional definitions excluded organically derived material. However, the International Mineralogical Association in 1995 adopted a new definition:

a mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes.

The modern classifications include an organic class - in both the new Dana and the Strunz classification schemes.

The chemical composition may vary between end members of a mineral system. For example the plagioclase feldspars comprise a continuous series from sodium-rich albite (NaAlSi3O8) to calcium-rich anorthite (CaAl2Si2O8) with four recognized intermediate compositions between. Mineral-like substances that don't strictly meet the definition are sometimes classified as mineraloids. Other natural-occurring substances are nonminerals. Industrial minerals is a market term and refers to commercially valuable mined materials (see also Minerals and Rocks section below).

Ore deposits are mineral deposits defined as being economically recoverable. Mineral deposits may include those bodies of mineralisation which are uneconomic resources, of too low a grade or tonnage or technically impossible for extraction of the contained metal.

What is valuable to mine is generally considered in terms of purely economic considerations. However, cultural, strategic or social goals of nations, tribes, and individuals may render economically unfeasible bodies of rock valuable for extraction, for instance ochre, some clays, and ornamental stones that are of religious, cultural or

sentimental value to a population. Here, value is placed on the rock in non-economic terms.

Rare samples of ore in the form of exceptionally beautiful crystals, exotic layering (when sectioned or polished) or metallic presentations such as large nuggets or crystalline formations of metals such as gold or copper may command a value far beyond their value as mere ore or raw metal for subsequent reduction to utilitarian purposes.

Ore is thus an economic entity, not a physical entity. Fluctuations in commodity prices will determine what rock is considered valuable and hence ore, and what rock is not valuable and is considered waste. Similarly, the costs of extraction may fluctuate, for example with fuel costs, rendering mining unprofitable and turning ore into waste.

The grade or contained concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining the ore. The cost of extraction must thus be weighted against the contained metal value of the rock and a 'cut-off grade' used to define what is ore and what is waste.

Ore minerals are generally oxides, sulfides, silicates, or "native" metals (such as native copper) that are not commonly concentrated in the Earth's crust or "noble" metals (not usually forming compounds) such as gold. The ores must be processed to extract the metals of interest from the waste rock and from the ore minerals.

Ore bodies are formed by a variety of geological processes. The process of ore formation is called ore genesis.

Extraction The basic extraction of ore deposits follows the steps below;

1. Prospecting or Exploration to find and then define the extent and value of ore where it is located ("ore body")

2. Conduct resource estimation to mathematically estimate the size and grade of the deposit

3. Conduct a pre-feasibility study to determine the theoretical economics of the ore deposit. This identifies, early on, whether further investment in estimation and engineering studies is warranted and identifies key risks and areas for further work.

4. Conduct a feasibility study to evaluate the financial viability, technical and financial risks and robustness of the project and make a decision as whether to develop or walk away from a proposed mine project. This includes mine planning to evaluate the economically recoverable portion of the deposit, the metallurgy and ore recoverability, marketability and payability of the ore concentrates, engineering, milling and infrastructure costs, finance and equity requirements and a cradle to grave analysis of the possible mine, from the initial excavation all the way through to reclamation.

5. Development to create access to an ore body and building of mine plant and equipment

6. The operation of the mine in an active sense 7. Reclamation to make land where a mine had been suitable for future use

Important ore minerals • Argentite: Ag2S for production of silver • Barite: BaSO4 • Bauxite Al2O3 for production of aluminium • Beryl: Be3Al2(SiO3)6 • Bornite: Cu5FeS4 • Cassiterite: SnO2 • Chalcocite: Cu2S for production of copper • Chalcopyrite: CuFeS2 • Chromite: (Fe, Mg)Cr2O4 for production of chromium • Cinnabar: HgS for production of mercury • Cobaltite: (Co, Fe)AsS • Columbite-Tantalite or Coltan: (Fe, Mn)(Nb, Ta)2O6 • Galena: PbS • Gold: Au, typically associated with quartz or as placer deposits • Hematite: Fe2O3 • Ilmenite: FeTiO3 • Magnetite: Fe3O4 • Molybdenite: MoS2 • Pentlandite:(Fe, Ni)9S8 • Pyrolusite:MnO2 • Scheelite: CaWO4 • Sphalerite: ZnS • Uraninite (pitchblende): UO2 for production of metallic uranium • Wolframite: (Fe, Mn)WO4