Question

An element has 18 electrons, and 20 .neutrons. Its charge is —2. What is its mass number?

• 1. 38
• 2. 32
• 3. 39
• 4. 40

Answer 1

Dear Student,

Atomic mass of element = Number of proton + Number of neutron

Number of proton = Number of electron

It is given that charge on element is -2 it means it is anion.

Atomic mass = 18 + 20 = 38 Answer

Regards