Question

How many neutrons and protons are there in the following nuclei?
${}_6^{13}\text{C}{,}_8^{16}\text{O}{,}_{12}^{24}\text{Mg}{,}_{26}^{56}\text{Fe}{,}_{38}^{88}\text{Sr}$

Answer 1

${}_6^{13}\text{C}:$
Atomic mass = 13
Atomic number = Number of protons = 6
Number of neutrons = (Atomic mass) – (Atomic number)
= 13 – 6 = 7

${}_8^{16}\text{O}:$
Atomic mass = 16
Atomic number = 8
Number of protons = 8
Number of neutrons = (Atomic mass) – (Atomic number)
= 16 – 8 = 8

${}_{12}^{24}\text{Mg}:$
Atomic mass = 24
Atomic number = Number of protons = 12
Number of neutrons = (Atomic mass) – (Atomic number)
= 24 – 12 = 12

${}_{26}^{56}\text{Fe}:$
Atomic mass = 56
Atomic number = Number of protons = 26
Number of neutrons = (Atomic mass) – (Atomic number)
= 56 – 26 = 30

${}_{38}^{88}\text{Sr}:$
Atomic mass = 88
Atomic number = Number of protons = 38
Number of neutrons = (Atomic mass) – (Atomic number)
= 88 – 38 = 50