# Melting points of alkali metal halides

The correct order of melting point of alkali metal halides is:

1. $$\ce{MF}>\ce{MCl}>\ce{MBr}>\ce{MI}$$
2. $$\ce{MI}>\ce{MBr}>\ce{MCl}>\ce{MF}$$
3. $$\ce{MCl}>\ce{MF}>\ce{MBr}>\ce{MI}$$
4. $$\ce{MI}>\ce{MF}>\ce{MCl}>\ce{MBr}$$

The correct answer to this is option (1), the reason I could think of is that as the size of anion in ionic compound increases the covalent character increases and hence the melting point decreases.