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.

GalliumGermanium Predicted in 1871 Discovered in 1875 Predicted in 1871 Discovered in 1886 Atomic Mass Density Melting PointLow30 o CHigh2830 o C Solubility in Acid Medium 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 ) Questions pg 206 1, 5, 7, 8 (Ch 5.3) Questions pg 211 1, 3, 4, 5, 10