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If the mass number of an atom is A = 40 ...

If the mass number of an atom is `A = 40` and its electron configuration is `1 s^2, 2 s^2, 2 p^6, 3 s^2 , 3p^6`, the number of neutrons and protons in its nucleus will be.

A

22,18

B

18,22

C

20,20

D

18,18

Text Solution

Verified by Experts

The correct Answer is:
A
(a) Number of protons `= 2 + 2 + 6 + 2 + 6 = 18`
Number of neutrons `= 40 - 18 = 22`.
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