Question

The total number of neutrons in dipositive zinc ions with mass number $70$ is:
A. $34$
B. $40$
C. $36$
D. $38$

Answer 1

As we know that the atomic number of zinc atoms is $30$. The number of electrons and protons of an atom is equal to the atomic number of the mass. Another important thing to note is that the mass number of an atom equals the sum of the number of protons and neutrons of the atom.

Complete step by step solution:

A zinc atom has an atomic number of $30$. The dipositive zinc ion has $2$ electrons less than $30$.
It has $28$ electrons.
The number of protons in the dipositive zinc ion will be $30$.
The sum of protons and neutrons is equal to the atomic mass of the ion.
Zinc has an atomic mass of $70$. So to find the number of neutrons, we can follow the below equation:
$mass = neutron + proton$
$\Rightarrow 70 = neutron + 30$
$\Rightarrow neutron = 40$

From the above explanation and calculation it is very clear to us that the correct answer of the given question is $40$

Hence, the correct answer is option B.

Additional Information:

Zinc is a very important element. It is used in the galvanisation process.
It is galvanised to protect some metals like iron from rusting . Zinc is used in automobile industries, electrical industries and hardware industries.
Zinc is an important element for the human body too. It improves the immune system, improves growth and metabolism of the human body.
It is found in some food like dairy products ,whole grains and cereals.

Note: Always remember that the atomic number is equal to the number of protons and electrons of the atom. The mass number of an atom is equal to the sum of the proton and neutrons of the atom. The process in which an electron is removed from an atom is called oxidation and the process in which an electron is added to an atom is called reduction.