Question

How many protons, neutrons and electrons are present in a carbon-12 atom? [1 Mark]

Answer 1

Carbon-12 is an isotope of carbon having an atomic mass number of 12.
The atomic number of carbon is 6.
Thus, number of protons in carbon-12 = 6.
In a neutral atom, number of electrons = number of protons.
Thus, number of electrons in carbon-12 = 6.
Mass number = no. of protons + no. of neutrons
Hence, no. of neutrons = 12 - 6 = 6.
[1 Mark]