The atomic numbers of four elements A,B,C and D are 12,13, 15 and 3 respectively. The element which cannot form a cation is :

The atomic numbers of four elements, A,B,C and D are 6,8,10 and 12 respectively. The two elements which can react to form ionic bonds (or ionic compounds) are:

Which element cannot form a cation ?

Which element cannot form a cation ?

Which element can not form a cation ?

Which element can not form a cation ?

The atomic numbers of four elements A,B,C and D are 6,10,12 and 17 respectively. Which two elements combine to form a covalent compound ?

The atomic numbers of four element P,Q,R and S are 6,10,12 and 17 respectively. Which two elements can combine to form a covalent compound?