Question

What is the total number of neutrons in an atom of 0-18?

Answer 1

Answer: The number of neutrons in given isotope are 10

Explanation:

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

The isotopic representation of an atom is: $_Z^A\textrm{X}$

where,

Z = Atomic number of the atom

A = Mass number of the atom

X = Symbol of the atom

We are given:

An isotope having formula:  $_{8}^{18}\textrm{O}$

Atomic number = Number of protons = 8

Mass number = 18

Number of neutrons = 18 - 8 = 10

Hence, the number of neutrons in given isotope are 10

Answer 2

A = mass number, A = protons + neutrons 
Z = atomic number, Z = protons 
neutrons = A - Z 
neutrons = 18 - 8 = 10