Which atomic number will atoms of 3Li combine with?

Answer 1

I think you want boron-10. This isotope of boron will react with Li to produce tritium, 3H3, albeit at very high energies.

Answer 2

Lithium is a very reactive element and would react with lots of non metals. Lithium form a 1+ ion in ionic reactions, so you can couple it with most nonmetals
eg with group VII elements: LiF, LiCl etc
with group VI elements: Li2O, Li2S etc.
with group V elements: Li3N etc