Chapter 8
Journey Inside the Atom
CBSE Class 9
Science Solutions
Educart Science class Class 9 NCERT Exemplar cover
Question:

The nucleus of an atom contains 20 protons. If its mass number is 41, find the number of neutrons in it. [Pg. No. 150]

Answer: Verified

Number of protons = 20

Mass number = 41

Number of neutrons

= Mass number – Number of protons

= 41 – 20 = 21

Therefore, the number of neutrons = 21.

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More NCERT Questions
Identify the number of electrons in the outermost shell of the following elements: (A) 612C(B) 919F(C) 1428Si [Pg. No. 152] If a bromine atom is available in the form of, say two isotopes, 3579Br (49.7\%) and 3581Br (50.3\%), calculate the average atomic mass of the bromine atom. [Pg. No. 156] Write the electronic configuration of the elements having atomic numbers 12, 16 and 18. [Pg. No. 152] Two different atoms have 11 protons each, but one has 12 neutrons, and the other has 13 neutrons. How do their atomic numbers and mass numbers compare? Are they the same element or different elements?