Question

1s2 2s2 2p6 3s2 3p6 3d8 ...the number of neutrons in the nucleus is

Answer 1

Given,

Electronic configuration of the atom = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁸

∴ Total; number of the Electrons = 28

We know that this is the Electronic configuration of the Nickel.

∴ Mass number or Atomic Mass =  59 g/mole.  (approximately)

We know the Formula,

Mass number = Atomic number + no. of neutrons.

⇒ no. of neutrons = Mass number - Atomic number.

∴ No. of Neutrons = 59 - 28

⇒ No. of neutrons = 31

Hope it helps.