Which of the following is true

i) Be is not affected by dry air

ii) Be is amphoteric metal

iii) Be has a maximum covalency Four

Beryllium does not react with air, due to its small size and I.E
Beryllium is amphoteric metal that means it reacts with both acids as well as bases.
"Be" does not exhibit coordination number [Covalency] more than "4" since its valency shell [n=2] has only 4 - orbitals
 

So option I,II,III are correct