GCSE C4.1

They form an alkaline solution when they react with water

They have one electron on their outer shell

• soft (can easily be cut with a knife)

• low density

• low melting point

• very reactive (only needs to lose 1 electron to become stable)

• melting point decreases as you go down the group due to decreasing attractive forces between outer shell electrons and positive ions

• softer as you move down

• reactivity increases

• the outer shell electrons get further away from nucleus so there are weaker forces of attraction between them

• less energy is needed to overcome the forces of attractions so outer electron is lost more easily

They react readily with oxygen and water vapour in the air

Metal hydroxide + Hydrogen

2Na (s) + 2H20 (l) --> 2NaOH (aq) +H2 (g)

Metal oxide

4Li + O2 --> 2Li2O

Metal chloride

2Li + Cl2 --> 2LiCl

Noble gases

• inert

• low density

• low boiling/melting point

unreactive
they have a full outer shell of electrons

Boiling points increase as you go down due to an increase in atomic mass so more intermolecular forces that need more energy to break

Halogens

poisonous

non-metals

diatomic

reactive

increasing melting point

increasing intermolecular forces so more energy needed to break them

yellow gas

pale green gas

red-brown liquid orange in solution

purple-black solid dark brown in solution

fluorine and chlorine - gas

bromine - liquid

iodine - solid

They have different melting and boiling points

the forces of attraction between the nucleus and outer shell decreases so harder for atoms to gain an electron

• hard and strong

• lustrous

• good conductors of heat and electricity

• highly dense metals

• very high melting points

colourful compounds

Scandium and Zinc - they don't form colourful compounds

catalysts like in the haber process with iron