Neutron Chemistry Example 1

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easy

An atom of sodium has a mass number of 23 and an atomic number of 11. How many neutrons does it contain?

1
Recall that the mass number $A$ equals the total number of protons plus neutrons: $A = Z + N$ .
2
Rearrange to find the neutron count: $N = A - Z$ .
3
Substitute: $N = 23 - 11 = 12$ neutrons.

Answer

12\text{ neutrons}

Neutrons contribute to the mass of an atom but not its charge. The mass number is the total count of protons plus neutrons in the nucleus.

About Neutron

A neutral subatomic particle found in the nucleus of an atom that has no electric charge but contributes to the atom's mass.

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