Compare and contrast the properties of halogens & alkali metals

Physical Properties

Alkali metals are good conductors of heat and electricity while halogens are poor conductors of heat and electricity.

Only specific to Alkali metals: They are soft and can be cut by knife.

Chemical Properties

Alkali metals have 1 valence electron while halogens have 7 valence electrons.

Alkali metals react with non-metals to form ionic compounds while halogens react with non-metals to form covalent compounds.

You can also look at the trends ( melting/boiling point, reactivity) down their group.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.