Question

Find the number of neutrons in silver having an atomic mass of 107.86.
(A) 65
(B) 71
(C) 61
(D) 47

Answer 1

Hint: Atomic number of silver is 47. Atomic number indicates numbers of protons present in the nucleus or number of electrons outside the nucleus. The mass number indicates the total number of protons and neutrons present in the nucleus. The number of neutrons can be calculated by taking the difference between mass number and atomic number.

Complete solution step by step:
-Atomic number indicates the number of protons present in the nucleus.
-Atomic number also indicates the number of electrons revolving outside the nucleus.
-In a neutral atom, the number of protons is equal to the number of electrons.
-The mass number represents a total number of protons and neutrons present in the nucleus.
-The mass number can be obtained by taking the sum of a number of protons and neutrons present in the nucleus.
-Atomic number of silver is 47 which indicates the number of protons present in the nucleus is 47.
Also, the number of protons is equal to a number of electrons.
The mass number is 107.86 which indicates the sum of the number of protons and neutrons in the nucleus is 107.86 which is approximately equal to 108.
So, Mass number=number of protons + number of neutrons
108=47 + number of neutrons
Number of neutrons=61

So, Find the number of neutrons in silver having an atomic mass of 107.86 is (C) 61.

Note: Mass number indicates sum of protons and neutrons present in the nucleus which is also called nucleons. Atomic number indicates the number of electrons or number of protons. So, the number of neutrons can be calculated by taking the difference of a mass number and atomic number