Why melting point decrease down the group for Alkali metals but increase for Halogens?

Answer 1

Because the atomic radius increases down the group 1 and decreases down the group of halogen

Answer 2

The melting point decreases down the group for alkali metals because the metallic bonding weakens as the atomic size increases, resulting in weaker intermolecular forces. For halogens, the melting point increases down the group due to stronger van der Waals forces between larger molecules with increased electron cloud size, resulting in higher melting points.

Answer 3

because of its increasing atomic size

Answer 4

No it is wrong. it is increasing.

Answer 5

Yes, they do.