Who introduced a simple notation to denote the valence electrons in an atom?

When a metal atom becomes an ion

Since the formation of an electrovalent bond involve a transfer of electrons,it can be regarded as

  Which is an example of giant structure of ions?

Which contains a co-ordinate bond?

Ammonia forms how many covalent bonds?

Ionic compounds are soluble in 

Which compounds have definite crystal lattice?

The number of electrons donated or accepted by the valence shell of an atom of an element to achieve stable electronic configuration is 

Number of electrons present in the valence shell of all the noble gases except helium is