The following data represents the distribution of electrons, protons and neutrons in atoms of four elements A, B, C, D

The following data represents the distribution of electrons, protons and neutrons in atoms of four elements A, B, C, D.

Answer the following questions:
(a) Give the electronic distribution of element B.
(b) The valency of element A.
© The atomic number of element B.
(d) The mass number of element D.

(a) Electronic distribution of elements B : 2,8,6
(b) Valency of A is 1 (-1).
© Atomic number of element Bis 16.
(d) Mass number of element D is 39.