In the following diagram for the first three periods of the periodic table, five elements have been represented by the letters a, b, c, d and e (which are not their chemical symbols):
(i) Select the letter which represents a halogen.
(ii) Select the letter which represents a noble gas.
(iii) What type of bond is formed between a and b?
(iv) What type of bond is formed between c and b?
(v) Which element form a divalent anion?
Give reasons for your choices.