Readily react with oxygen and water; stored in oil

Good conductors of heat and electricity

React violently with chlorine

Soft and easy to cut

Burst into flames when heated with oxygen[red flame for lithium; yellow flame for sodium; lilac flame for potassium]

Shiny when freshly cut

Produce soluble white compounds.

Low melting and boiling points compared to most metals.

React with water to form alkaline metal and hydrogen gas

Low densities for metals

States and Colors, at RTP:
Fluorine- Yellow gas
Chlorine- Green gas
Bromine- Red liquid
Iodine- Black solid

Down the group; size, mass and density increase

Poisonous

Down the group, color darkens

Diatomic; form halide ions in displacement reaction

Reactivity decreases down the group,
because it has to gain an electron,
so the closer the electron is to the positive nucleus the more easily it will be gained,
so atoms with fewer shells will react more easily.

Do not conduct electricity

melting point increases down the group

Brittle and crumbly when solid

Density increases down the group

Helium- filling balloons and aircrafts because it is lighter than air and will not catch fire.

Monoatomic and colorless

Argon – filling (tungsten) light bulbs to stop the filament reacting with oxygen.

M.P. and B.P. increases down the group

Neon – is used in advertising signs because it glows red.

Don’t conduct electricity

Inert due to full outer shell electrons