Alkali metal

How many metals are there in group 1

as the metal moving down in the group, the melting point will increase. true/false?

as the metal moving down in the group, the boiling point will decrease. true/false?

when alkali metal react with water, it will produce an alkaline solution. true/false?

when alkali metal react with water, what kind of gas is produced?

as the metal moving down in the group, what is the trends for density?

Among potassium, sodium and lithium. Which metal is the most reactive?