The atomic number of three elements A ,B and C are 9,10 and 13 respectively .which one of then will form a cation

The atomic numbers of three elements A, B and C are 11, 13 and 19 respectively. Explain which two of the elements will belong to the same group of the periodic table.

The atomic numbers of three elements X, Y and Z are 9, 11 and 17 respectively. Which of these two elements will show similar characteristics and why ?

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 nubers of the elements A, B, C and D is 9, 10, 11 and 12 respectively. The correct order of ionization energies 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:

The atomic number of two elements A and B are 17 and 20 respectively. The formula of ionic compound made by A and B is (where the cation is conventionally written first)