AGENDA•GET TO KNOW PERIODIC TABLE AND HISTORY•MAKE YOUR OWN PERIODIC TABLE

DO NOWGrab packet and periodic table

1. Study these ions with a partner:acetate, bromate, chlorate, chlorite, cyanide,

bicarbonate

REMINDERS•ION QUIZ FRIDAY

THE PERIODIC LAW

Chemistry Chapter 5

Mendeleev’s Periodic Table

Dmitri Mendeleev

Mendeleev – organized periodic table

Tried to organize periodic table according to properties

Vertical columns in atomic mass orderMade some exceptions to place elements in

rows with similar properties (Tellurium and Iodine)

Horizontal rows have similar chemical properties

Gaps for “yet to be discovered” elementsLeft questions: why didn’t some elements fit in

order of increasing mass? Why did some elements exhibit periodic behavior?

Henry Moseley

Discovered that periodic table was in atomic number order, not atomic mass order

Explained the Te-I anomaly

Periodic Law

Physical and chemical properties of the elements are periodic functions of their atomic numbers

Modern Periodic Table

Discovery of noble gases yields new family (Group 18 – aka inert gases)

Lanthanides (#58 - #71)Actinides (#90 – #103)

Periods and Blocks of the Periodic Table

Periods – horizontal rows Corresponds to highest principal quantum number

Groups/Families – vertical columns; these elements share similar chemical properties (they have the same number of valence electrons)

Blocks – periodic table can be broken into blocks corresponding to s, p, d, f sublevels

Orbital filling table

s block

S block includes groups 1 and 2Group1 – “The alkali metals” One s electron in outer shellSoft, silvery metals of low density and low

melting pointsHighly reactive, never found pure in nature

s block

Group 2 – “Alkaline Earth Metals”2 s electrons in outer shellDenser, harder, stronger, less reactive than

Group 1Too reactive to be found pure in nature

Periodic Table with Group Names

Easily lose valence electron (Reducing agents)

React violently with waterReact with halogens to form

salts

The Properties of a Group: the Alkali Metals

d block

Groups 3 -12Metals with typical metallic propertiesReferred to as transition metalsGroup number = sum of outermost s and d

electrons

p block

Groups 13-18Properties vary greatly – metals, metalloids,

and nonmetalsGroup 17 – halogens are most reactive of non

metalsGroup 18 – noble gases are NOT reactive

f block

Lanthanides – shiny metals similar to group 2Actinides – all are radioactive; plutonium –

lawrencium are man-made

Make your own periodic table!

1. Number the groups (18) 2. Number the periods (7) 3. Draw a heavy lack line between the metals and nonmetals. 4. Write the symbol of each element that exists as a gas at ordinary conditions in

RED. 5. Write the symbol of each element that is a solid at ordinary conditions in

BLACK. 6. Write the symbol of each element that is a liquid at ordinary condition in BLUE. 7. Write the symbol of each element that is a man-made element as an outline. 8. Place the atomic number for each element above the symbol. 9. Color each of these a different color and make a key at the bottom:

Halogen (group 17) Noble gases (group 18) Alkali metals (group 1) Alkaline earth metals (group 2) Transition elements (group 3-12) Lanthanides Actinides Metalloids Post-transition metals Other non-metals

10. Outline the symbol’s box in dark green if it is RADIOACTIVE in its most common form.

Properties of Metals

Metals:

good conductors of heat and electricity

Malleable

Ductile

Have high tensile strength

luster

Examples of Metals

Potassium, K reacts with water and must be stored in kerosene

Zinc, Zn, is more stable than potassium

Copper, Cu, is a relatively soft metal, and a very good electrical conductor.

Mercury, Hg, is the only metal that exists as a liquid at room temperature

Properties of Nonmetals

Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.

Nonmetals are: poor conductors of heat and electricity brittleMany are gases at room temperature

Examples of Nonmetals

Sulfur, S, was once known as “brimstone”

Microspheres of phosphorus, P, a reactive nonmetal

Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

Properties of Metalloids

Metalloids straddle the border between metals and nonmetals on the periodic table.

They have properties of both metals and nonmetals.Metalloids are more brittle than metals, less brittle than most nonmetallic solids Metalloids are semiconductors of electricity

Many used in computer parts Some metalloids possess metallic luster

Silicon, Si – A Metalloid

Silicon has metallic luster Silicon is brittle like a nonmetal Silicon is a semiconductor of electricity

Other metalloids include:

Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te

Half of the distance between nuclei in covalently bonded diatomic molecule

"covalent atomic radii"

Periodic Trends in Atomic Radius

Radius decreases across a period Increased effective nuclear charge dueto decreased shielding

Radius increases down a group

Addition of principal quantum levels

Determination of Atomic Radius:

Table of Atomic Radii

Increases for successive electrons taken from the same atom

Tends to increase across a period

Electrons in the same quantum level do not shield as effectively as electrons in inner levels

    Irregularities at half filled and filled sublevels due to extra repulsion of electrons paired in orbitals, making them easier to remove

Tends to decrease down a group

Outer electrons are farther from thenucleus

Ionization Energy - the energy required to remove an

electron from an atom

Ionization of Magnesium

Mg + 738 kJ Mg+ + e-

Mg+ + 1451 kJ Mg2+ + e-

Mg2+ + 7733 kJ Mg3+ + e-

Table of 1st Ionization Energies

Another Way to Look at Ionization Energy

Ionic Radii

Cations Positively charged ions Smaller than the

corresponding atomAnions Negatively charged

ions Larger than the corresponding atom

Table of Ion Sizes

Electronegativity

A measure of the ability of an atom in a chemicalcompound to attract electrons

Electronegativities tend to increase across a period

* more nuclear charge, more power to attract electrons

Electronegativities tend to decrease down a group or remain the same

* additional energy levels result in less attraction to the nucleus

Periodic Table of Electronegativities