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)

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:

The values of electronegativity of atom A and B are 1.20 and 4.0 respectively. The percentage of ionic character of A-B bond is nearly

Two elements, Xand Y, have atomic numbers 33 and 17 , rspectively. The molecular formula of a stable compound formed between them is-

(a) List two limitations of Newlands' Law of Octaves. (b) Write the electronic configuration of two elements A and B whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element A reacts with element B. State whether this compound is acidic, basic or neutral. Give reason to justify your answer.