Atomic number of three elements A,B and C are 8, 13 and 17 respectively
(1) Write their electronic configuration.
(2) Ascertain their positions in the periodic table.

Explanation

(1) Electronic configuration of `""_(9)A:1s^(2)2s^(2)2p^(5)`,
`""_(13)B:1s^(2)2s^(2)2p^(6)3s^(2)3p^(1),""_(17)C:1s^(2)2s^(2)2p^(6)3s^(2)3p^(5)`
(2) All the three elements are p-block elements. Hence, their group and period numbers are as follows:
.