Answer: Number of neurons in
Helium = 1
Carbon = 8
Nitrogen = 8
Strontium = 52
Tellurium = 71
Explanation: Isotopes are the forms of same element having different mass numbers. They only differ in the number of neutrons. The number of protons remain same. [tex]_{Z}^{A}\textrm{X}[/tex] and [tex]_{Z}^{B}\textrm{X}[/tex] are the two isotopes of same element X.
Neutrons can be calculated by:
Number of neutrons = Mass Number - Number of neutrons
and Atomic Number = Number of protons
For the given elements, Mass numbers are given
Atomic Number of Helium = 2
Given mass number = 3
Number of neutrons in Helium= (3 - 2) = 1
Similarly,
Number of neutrons in Carbon = (14 - 6) = 8
Number of neutrons in Nitrogen = (15 -7) = 8
Number of neutrons in Strontium = (90 - 38) = 52
Number of neutrons in Tellurium = (123 - 52) = 71
