Atoms And Nuclei Question 260
Question: If the mass number of an atom is $ A=40 $ and its electron configuration is $ 1s^{2},\ 2s^{2},\ 2p^{6},\ 3s^{2},\ 3p^{6} $ , the number of neutrons and protons in its nucleus will be [RPMT 2002]
Options:
A) 22, 18
B) 18, 22
C) 20, 20
D) 18, 18
Show Answer
Answer:
Correct Answer: A
Solution:
Number of protons = 2 + 2 + 6 + 2 + 6 = 18 Number of neutrons = 40 ? 18 = 22.
