Question

To what characteristics of the group 1 metallic elements can the ease with which their sons form +1 monatomic ions be attributed?

Answer 1

Group 1 elements (usually called alkali metals) are not very electronegative and have small ionization energies due to that. The reason why they are not very electronegative is that they really want to loose their one valence electron so that they can have a noble gas electron configuration (completed octet).

I hope this helps.