Question 12 — An atom has 79 protons - Questions at the end of the chapter - Chapter 8 - Journey Inside the Atom (Exploration)

Last updated at July 3, 2026 by

Question 12
An atom has 79 protons and a mass number of 197. Calculate (i) the number of neutrons, and (ii) the number of electrons.
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  • (i) Neutrons = A − Z = 197 − 79 = 118 .
  • (ii) Electrons = protons = 79 (neutral atom). This element is gold, Au.
Neutrons and Electrons Neutrons equal A minus Z equals 197 minus 79 equals 118; electrons equal protons equals 79.
Back to: 8.6 Mass Number
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