The Periodic Table

History

Dimitri Mendeleev (~1850’s) – inventor of the modern periodic table.– Elements arranged according to their

properties. Ex. Atomic mass, solubility, density, flammability.

– Started a new column when elements properties matched.

Gallium Germanium

Predicted in 1871

Discovered in 1875

Predicted in 1871

Discovered in 1886

Atomic Mass 68 69.9 72 72.3

Density 5.9 5.94 5.5 5.47

Melting Point Low 30oC High 2830oC

Solubility in Acid

Medium Medium Low Low

Groups / Families

• Vertical columns

• Similar chemical and physical properties.– Have the same number of electrons in

their outer orbit.– Special named columns: Alkali Metals,

Alkaline Metals, Halogens, Nobel Gases, Hydrogen and Metalloids

Alkali Metals (Fam.1)• Lithium, Sodium, Potassium,

Rubidium, Cesium, Francium

• Shiny, silvery metals

• Very reactive – combine with other elements easily

• Outer orbit (valence orbit) has only 1 electron

Alkaline Earth Metals (Fam.2)

• Beryllium, Magnesium, Calcium, Strontium, Barium, Radium

• Shiny metals

• Reactive

• Outer orbit has 2 electrons

Halogens (Fam.17)• Fluorine, Chlorine, Bromine, Iodine,

Astatine

• Non-metals

• Very Reactive

• Outer orbit has 7 electrons(i.e. is 1 electron short of being full).

Noble Gases (Fam.18)• Helium, Neon, Argon,

Krypton, Xenon, Radon

• Gases at room temperature

• Very stable and inert – don’t react

• Outer orbit of electrons is full.

Hydrogen• Unique.

• Colourless, odourless, tasteless, highly flammable gas.

• Doesn’t lose or gain electrons but shares it’s one electron.

Metalloids• Found on either side of the

zig-zag line separating metals and non-metals.

• Have both metallic and non-metallic properties.

• NOTE: Metals Left of line Nonmetals Right

of line

• Read 194 – 200, 205 – 211 (Ch. 5.3-5.4)

• Questions pg 206 1, 5, 7, 8 (Ch 5.3)• Questions pg 211 1, 3, 4, 5, 10