Question

How many protons, electrons and neutrons are there in the following nuclei?

i. \(_8^{17}O\) 

ii. \(_{12}^{25}Mg\) 

iii. \(_{35}^{80}Br\) 

Answer 1

i. \(_8^{17}O\) 

Atomic number, Z = 8, 

Mass number, A = 17 

Number of protons = Number of electrons = Z = 8

Number of neutrons (N) = A – Z = 17 – 8 = 9

Number of protons = 8, 

Number of electrons = 8, 

Number of neutrons = 9

ii. \(_{12}^{25}Mg\) 

Atomic number, Z = 12, 

Mass number, A = 25

Number of protons = Number of electrons = Z = 12

Number of neutrons (N) = A – Z = 25 – 12 = 13

Number of protons = 12, 

Number of electrons = 12, 

Number of neutrons = 13

iii. \(_{35}^{80}Br\) 

Atomic number, Z = 35, 

Mass number, A = 80 

Number of protons = Number of electrons = Z = 35

Number of neutrons (N) = A – Z = 80 – 35 = 45

Number of protons = 35, 

Number of electrons = 35, 

Number of neutrons = 45