Determine the number of neutrons for the given isotopes. helium-3 carbon-14 nitrogen-15 strontium-90 tellurium-123

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. and 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

14 days is the half-life of phosphorus-32