Question

Zirconium has an atomic number of 40. How many neutrons are there in the isotope of zirconium-92?

Answer 1

The given isotope is Zirconium-92 where the value 92 is the mass number of the zirconium atom. The number of neutrons is calculated by subtraction of the mass number with the atomic number. The value of the atomic number is the same as the proton number.

Complete step by step answer: Given,
Atomic number of zirconium is 40.
The atom contains a center nucleus which contains a positively charged proton and neutral charged neutron. The negatively charged electrons are surrounding the atom in a circular orbit.
The atomic number of an atom is equal to the number of protons present in the atom. The number of protons is equal to the number of electrons.
The isotopes are defined as the species which have similar atomic numbers but differ in the mass number. The mass number is calculated by adding the number of protons and number of neutrons. In isotopes, the mass number as well as the number of neutrons changes.
Hence the neutron of the atom will be calculated by subtracting the mass number with the atomic number of the atom (number of protons).
$number\;of\;neutrons = mass\;number - atomic\;number$
The isotope of zirconium given is zirconium-92 where the value 92 is the mass number of the zirconium.
So, the number of neutrons is calculated as shown below.
$\Rightarrow number\;of\;neutrons = 92 - 40$
$\Rightarrow number\;of\;neutrons = 52$
Therefore, the number of neutrons present in isotope zirconium-92 is 52.

Note:
The average atomic mass of the atom is calculated summing up all the masses of the isotopes of the same element each multiplied with the natural abundance.