Group 1 (Alkali metals) & Group 7 (Halogens)

Group 1 metals?

Lithium, sodium, potassium, rubidium,caesium and francium

chemical properties?

• soft metal- can be easily cut with a knife

• relatively low densities and low melting points

• very reactive

reaction with water?

Group 1 metal + water = metal hydroxide + hydrogen

Lithium reaction with water?

• relatively slow reaction

• Fizzing

• Lithium moves on the surface

Sodium reaction with water?

• more vigorous fizzing

• moves rapidly on the surface of the water

• dissolves quickly

Potassium reaction with water?

• reacts more vigorously than sodium

• burns with a lilac flame

• moves very rapidly on the surface

• dissolves very quickly

reactions with oxygen?

group 1 metal + oxygen = metal oxide

Physical trends?

• soft and easy to cut- softer as you move down the group

• first three alkali metals are less dense than water

• low melting points- decreases as you move down the group because of decreasing attractive forces

halogen names?

fluorine, chlorine, bromine, iodine and astatine

Fluorine physical properties

Room temp- yellow gas

very reactive, poisonous gas

Chlorine physical properties?

Room temp- Pale yellow-green gas

reactive, poisonous and dense gas

solution- pale green

Bromine physical properties?

Room temp- red- brown liquid

dense, red-brown volatile liquid

solution- orange

iodine physical properties?

room temp- grey solid

shimmery, crystalline solid that sublimes to form a purple vapour

solution- dark brown

halogens reacting with metals?

halogens + metal = metal halide salts

halogens reacting with non-metals?

• forms simple molecular covalent structures

Displacement reactions?

a halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen