Which one of the following properties of alkali metals increases in magnitude as the atomic number rises ?

Which one of the following is an alkali metal?

Property of the alkali metals that increases with their atomic number is:

Which of the following properties of IA group metals increases as the atomic number rises: (a) Metallic character (b) Ionic radius (c ) Melting point (d) Density (e ) Ionization potential Correct answer is:-