Periodic Families

The Periodic Table

What does the word periodic mean? pe·ri·od·ic

 –adjective 1. recurring at intervals of time: periodic revivals of an interest in handicrafts.

2. occurring or appearing at regular intervals: periodic visits of a mail steamer to an island.

3. repeated at irregular intervals; intermittent: periodic outbreaks of the disease. From Dictionary.com

Choose 1 definition and know it!

Mendeleev and the Periodic Table Dmitri Mendeleev

A Russian developed the first periodic table in 1869

He based his table upon the physical properties of the elements

He was even able to predict the properties of undiscovered elements

He made the table 40 years before the discovery of the electron

A gentle reminder

Columns on the Periodic Table They are called Groups or Families

Rows on the Periodic Table Periods

Groups and families include similar elements Metals are on the left of the zig-zag line Non-metals on the right of the zig-zag line

How are the elements arranged The elements are arranged by number of

protons, the atomic number The elements are not in mass number

Ar, number 18, has a larger mass than K, number 19

The same thing happens with Co and Ni

A new term

Valance electrons Electrons in the outermost shell

Remember electron configuration Usually the S and P sub –orbital How many valence electrons in Na, or Cl

S can hold 2 and P can hold 6 How many elements in period 2?

Coincidence… I think not.

Remember your “People” from outer Space What did you notice as you move down a

column? What you did you notice as you across a

row? The same thing happens in the periodic

table.

Lets take a tour of the Periodic Families

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Group 1 Alkali MetalsKnow this group Metallic, soft Low melting point for a metal Highly reactive One valence electron

Group 2 Alkaline Earth MetalsKnow this group Higher melting points than alkali metals Soft and lightweight for a metal but harder that alkali

metals Low reactivity at room temperature 2 valence electrons Important compounds

Calcium oxide (lime) the 5th most produced chemical Calcium carbonate-chalk, marble, toothpaste abrasive and

antacid

Group 13 Boron Family

Metalloid Boron, Metal Al, Ga, In, Th Has 3 valance electrons Ions +3 Can be very hard (boron) Overall shiny, relatively soft and low melting point Can be excellent conductors (Al) Important compounds

Borax Aluminum oxide- used in sandpaper

Group 14 The Carbon Family

Non metal C, metalloid Si & Ge and metals tin and lead Has 4 valence electrons Density increases as you go down the group Hardness and melting point decrease as you go down the group Can form bonds with 4 other chemicals Important compounds

Methane CH4

Silicon dioxide- glass Buckminsterfullerene, nanotubes

Group 15 The Nitrogen Family Nonmetallic N, P; Metalloids arsenic, antimony (Sb)

and 1 metal bismuth 5 valence electrons, ion have a -3 charge Melting points increase then decrease Density increases steadily Important compounds

Ammonia NH3

Amino acids Bismuth subsalicylate

Group 16 Oxygen Family

Nonmetal O and S, metalloid Se and Te, lone metal polonium

6 valence electrons, has a charge of -2 Melting points increase Densities increase Important chemical

Water H2S the rotten egg smell, Hydrogen peroxide Sulfuric acid, the cheapest strong acid

Group 17 Halogen FamilyKnow this family Extremely reactive, F the strongest 7 valence electrons, charge of -1 Melting points increase but still well below 0 Densities increase Important compounds

HCl hydrochloric acid Bleach NaClO PCB

discontinued as a cancer risk Ammonium perchlorate

used in the shuttle

Group 18 Noble GasesKnow this family Eight valence electrons

Outer shell filled That is why He is in this group

Odorless colorless gases Unreactive

There are some exceptions

Reactivity in non metals

Reactivity in metals

Trends in reactivity

More reactive as you move down

More reactive as you move up

Atomic radius for metals increases

Atomic radius for non-metals decreases

Trends in atomic radius

Atomic radius decreases

• Least Metallic

• Most Reactive

V8

V2V4

• Positive ions

• Variable v-electrons

V6V5

V1

V2 V3 V7

Increasing reactivity

• Most reactive

• Most metallic

+1 +2 -2-3+/-4+3 0-1

Increasing reactivity

Unreactive gases

METALS

NON-METALS

METALLOIDS

V8

V2V4 V6V5

V1

V2 V3 V7

Ion Sizes

Metals form positive ions and become smaller

Non-metals form negative ions and get bigger.