Groups The vertical columns in the periodic table are called groups. These groups are I, II, III, IV, V, VI, VII, VIII All the elements in group I have 1 electron in their outermost shell All the elements in group II have 2 electrons in their outermost

How many electrons do you think are in the outermost shell of groups III, IV, V, VI, VII, VIII Lets check - Show that lithium, sodium and potassium have 1 electron in their outermost shell Show that fluorine and chlorine have 7 electrons in their outermost shell

Periods The horizontal rows of elements are called periods. The period number tells us the number of shells (orbits) in an atom of an element in that period. For example magnesium is in period 3 so it has 3 shells of electrons.

In which period is sodium? How many shells of electrons will sodium have? In which period is Neon? How many shells of electrons will neon have? In which period is calcium? How many shells of electrons will calcium have?

Metals and Non - Metals The periodic table is split into metals and non metals. Metals are found on the left side and non metals are found on the right side. Use the periodic table to help you decide if the following are metals or non metals: Sodium, chlorine, argon, calcium, iron, silver, carbon, potassium, copper, sulfur, oxygen

MetalsNon-metals SodiumChlorine CalciumArgon IronCarbon SilverSulfur PotassiumOxygen Copper

Group I – The Alkali Metals All have 1 electron in their outermost shell Li – Lithium (2,1) INCREASING Na – Sodium (2,8,1) REACTIVITY K – Potassium (2,8,8,1)

Properties of Alkali Metals Soft, easily cut with a knife Freshly cut surface is shiny and silvery Low densities – will float on water Low melting point Highly reactive, so stored under oil to stop reaction with air React with oxygen to form oxides React with water

Reaction of Alkali Metals with Oxygen Alkali metals lose their shiny surface when exposed to air. They form metal oxides Lithium + oxygen -> lithium oxide Sodium + oxygen -> sodium oxide

Reaction of Alkali Metals with Water Alkali metals react vigorously with water. Lithium + water -> lithium hydroxide + hydrogen Sodium + water -> sodium hydroxide + hydrogen Potassium + water -> ____________ + ________ Metal hydroxides are alkali and turn red litmus paper blue

Other Groups Group II – The Alkaline Earth Metals 2 electrons in outermost shell

Group VII – The Halogens 7 electrons in the outermost shell

Group VIII – The Nobel Gases Very unreactive elements because they have a full outer shell of electrons and are therefore stable All have an outer shell containing the full 8 electrons except helium which has 2 electrons in its outer shell