The Periodic Table

Elements & Families of Elements

Unit Outcomes

Number the periods (electron shells) Number the groups (valence number) Draw the line that separates the metals from

the nonmetals Write the oxidation numbers Identify atoms that are solid, liquid and gases

at room temperature

Unit outcomes, continued

Learn names and symbols of the elements shown below.

Unit Outcomes, continued

Identify trends across the periodic table Identify key properties of metals and nonmetals Locate the families

Alkali metals, Alkaline earth metals, transition metals, metalloids, Halogens, Noble gases

Identify key properties of families Learn key vocabulary—solid, liquid, gas, ‘full’,

reactive, conductor, brittle, melting point, etc.

Periodic Table

Elements Defined

Elements are substances that cannot be broken down into simpler substances by ‘ordinary’ chemical means such as by heat, light, electricity, or reaction with other substances special equipment, such as a particle

accelerator, or temperatures like those inside the sun can break down elements

Periods and Groups

Periods

Horizontal Rows are called PERIODSPeriod number = # of electron shells of

atoms in each row Period 1 atoms all have 1 electron shell Period 2 atoms all have 2 electron shells … etc. Period 7 atoms all have 7 electron shells

Groups

Vertical Columns are called GROUPS Group number = # of electrons in the outermost

shell of atoms in each column Group 1 atoms have 1 electron in their outermost shell Group 2 atoms have 2 electrons in their outermost shells … etc. Group 8 atoms all have ‘full’ outermost shells

e.g., Helium has 2 e- in outermost shell e.g., Neon and argon have 8 e- in the outermost shell

Group Number/Valence Electrons

Group number = number of valence electrons Valence electrons—electrons in the outermost

shell determine how an atom combines with other atoms

its chemical properties

Group numbers can be written with Arabic (1, 2, 3, etc.) or Roman numerals (I, II, III, etc.) Use Roman numerals to avoid confusion

Ions

ION (definition) — an atom (or group of atoms) that is positively or negatively charged; a charged particle

Na+1 Na ---> Na+ + 1e- Be? Atom + ion donates an e-

B 11 p+ 11 p+

N 11 e- 10 e-

O F Cl + 1e- --- > Cl-

Atom accepts an e- - ion

17 p+ 17 p+

17 e- 18 e-

Electropositivity

the ability of an atom to lose electrons and form positive ions.

http://www.meta-synthesis.com/webbook/35_pt/pt.html

Electronegativity

the ability of an atom to gain electrons and form negative ions the stronger an atom pulls electrons, the higher its

electronegativity

Oxidation Numbers

The number of electrons donated (lost) or accepted (gained) by an atom Donate 1 to 4 electrons

Oxidation # +1, +2, +3, +4 Form positive ions (+1 ion, +2 ion, +3 ion, etc.)

Accept 1 to 4 electrons Oxidation # -4, -3, -2, -1 (-1 ion, -2 ion, -3 ion, etc.) Form negative ions

Do not donate/accept electrons Oxidation # 0

Atoms become stable (get ‘full’ outer shells) by donating or accepting valence electrons!

Oxidation Numbers

The Elements (1955)—A Song

Read the ‘lyrics’ as the song plays.

Pay attention to the pronunciation of the elements.

Can you sing along? Give it a try!

animation

by Tom Lehrer, Maths professor at Harvard

Solids, Liquids, Gases

Solids, Liquids, Gases

Liquids: Br, Hg

Gases: H, N, O, F, Cl, He, Ne, Ar, Kr, Xe, Rn

Solids: All other elements

Elements

Synthetic (man-made) Atomic numbers 43, 61, 93-118

Naturally occurring (found in nature) All other elements

Metals () and Nonmetals ()

Metals and NonMetals

Different electron cloud configurations of elements create (result in) different properties

Metals: outer shells with few electrons Tend to lose electrons, form positively charged

ions, in chemical reactions

Nonmetals: outer shells are nearly full Tend to gain electrons, form negatively charged

ions, in chemical reactions, OR share electrons and form a covalent bond

Metals VS Nonmetals

Metalsgood conductors of heat &

electricity

ductilecan be drawn out into wires

malleable (bendable)can be forced (hammered)

into different shapes

high melting points so solid at room temperature

form positive ions, cations

form basic oxides

NonmetalsGood electrical insulators;

nonconductors of electricity

brittle & crumbly in solid form

relatively low boiling points form negative ions, anions

form acidic oxides

Acids and Bases

Metals and Nonmetals

Metalsreact with nonmetals

to form compounds

Nonmetals (Group 7)very reactiveform ionic bonds with

metalsform covalent bonds

with other nonmetals

Trends: Metallic Properties

Metalloids and Diatomics

7 metalloids B, Si, Ge, As, Sb, Te, Po Intermediate (in between) physical and chemical

properties (metals and nonmetals) silicon and germanium, are semi-conductors (computers)

7 diatomics H, N, O, F, Cl, Br, I

H2, N2, O2, F2, Cl2, Br2, I2

Trends across the Periodic Table

as you move down a group ( )Atomic number, mass, density and size

(radius) increasesMelting points decrease (metals)/ increase

(nonmetals)Reactivity increases (metals)/ decreases

(nonmetals)

*Fr and F are 2 most reactive elements*

Trends across the Periodic Table

as you move across a period ( )Atomic number and mass increasesSize (radius) decreasesHardness and melting points increase

(metals) Reactivity decreases (metals)/ increases

(nonmetals)

Atomic Number and Mass

Size (atomic radii)

“Atoms with more

electrons will be bigger.”

top to bottom

X left to right

Why?

Protons (+)

AND

electron shells (-)

Summary of P.T. Trends

Metal Atoms: relatively large atoms with weak attraction for electrons

more metallic

Nonmetal Atoms: relatively small atoms with strong attraction for electrons

more nonmetallic

Mendeleev’s Periodic Table (1869)

Increasing atomic weight/mass Repeating chemical properties/reactivity in rows Left empty spaces…why?

Big Difference?

Other Possibilities?

Galaxies

Spirals

Which is your favorite?

Check out this website:

http://www.meta-synthesis.com/webbook/35_pt/pt.html

Families

Families

Definition: groups of elements that have similar chemical properties Chemical properties: valence number, reactivity

(with water, a base, an acid), behavior in solvents, radioactivity

Physical properties: state, color, m.p. and b.p., hardness, malleablility, density, conductivity, etc.

Examples of Families Alkali Metals, Alkaline Earth Metals, Transition

Metals, Halogens, the Noble Gases Found in columns and/or series (rows)

The Top and the Middle

Hydrogen, Helium and Transition Metals Hydrogen—properties of both group I and VII

sometimes missing an electron +1; sometimes with an extra electron -1; doesn’t belong to any family

Helium—placed in group VIII yet unlike all other elements, it can only have two

electrons in its outer shell

Transition Metals —in center section have special electron rules +2 (unless otherwise noted)

Cu I, Cu IV, etc.

Alkali Metals (Li, Na, K, Rb, Cs, Fr) Most reactive family of metals

Group I: only 1 e- in outer shell More reactive as move down the group, as size increases

Never found free in nature Kept under oil in lab

Metals (but not always typical metals*) Good conductors of heat/electricity Malleable and ductile All soft (can be cut with a knife) and shiny and lighter

(less dense) than other metals (float on water)* Solid at room temperature*

M.P and B. P are positive/lower than most metals

Alkali Metals

Form ionic compounds (+1 positive ion, cation) Compounds formed are white metallic solids Dissolve in water --> colourless solutions

Sodium chloride (NaCl) table salt

Very reactive with water (and chlorine and oxygen) React with water to form bases (alkaline solutions) …

‘Alkali’ metals

Sodium and potassium ions are important parts of body fluids (electrolytes)

Rb, Cs and Fr are dangerous (Fr is radioactive)

Alkali Earth Metals(Be, Mg, Ca, Sr, Ba, Ra) 2nd most reactive family of metals

Group II: 2 e- in outer shell Lose valence electrons and form positive ions, +2 charge

Never found free in nature

Metals Similar properties to alkali metals

Electrical conductors; malleable and ductile Silvery but harder and more dense, w/ higher M.P and B.P Form ionic compounds, react with water to form alkaline

suspensions Na and K, and Ca and Mg ions are important in our

bodies

Transition Metals

21 (Scandium) through 29 (Copper)

39 (Yttrium) through 47 (Silver)

57 (Lanthanum) through 79 (Gold)

89 (Actinium)

and all higher numbers

Transition Metals

able to put more than 8 e-

(up to 32 electrons) in the shell that is one in from the outermost shell gold (Au) 2-8-18-32-18-1

can use the two outermost shells to bond with other elements allows them to bond with many elements in a

variety of shapes

range of oxidation states

Transition Metals

Very good conductors of heat/electricity Malleable and ductile Hard, tough, strong High M.P. and density Low reactivity (compared to Group I and II Metals)

Most form brightly colored compounds Uses: building structures, electric cables,

radiators, colored paints, catalysts for industrial reactions, etc.

The Halogen Family(F, Cl, Br, I, At) Group XVII: 7 e- in their outer shell

Very reactive—with many different elements (especially Group I and II metals)

Form both ionic and covalent compounds (-1 anion) Never found free in nature; always in compounds

Nonmetals See: diatomics Electrical insulators Crumbly and brittle (solid) Characteristic colors and odors M.P. and B. P. are low solid (I2), liquid (Br2) or gaseous (F2 , Cl2) at R.T. Can be poisonous Used in bleaches, insecticides, dry cleaning, toothpaste

The Noble Gases(He, Ne, Ar, Kr, Xe, Rn) Group VIII: All have full outer shells (2 e- for

Helium, 8 e- for all others) Unreactive, ‘stable’ or ‘inert’ (no need to react!) Always found free in nature; monatomic

Nonmetals Colorless gases at R.T. (Earth’s atmosphere) Low B.P.

Uses: advertising signs and fluorescent lighting (neon), light bulbs (argon), car headlights (xenon), balloons and airships (helium), lasers (krypton)