Question

How do we explain the fact that cobalt comes before nickel in the periodic table, even though cobalt has a higher atomic mass than nickel?

Answer 1

Hint: Before solving this question, it is important to know the basic terms such as atomic number, electrons and protons. Atomic number is the number of protons present in the nucleus.

Complete step by step answer:
- Electrons, protons and neutrons are the subatomic particles. Electrons are the subatomic particle which carries a negative charge, while protons are the subatomic particle with a positive charge and neutrons are the subatomic particle which has no charge. Protons and neutrons both are present in the nucleus of the atom whereas electrons revolve around the nucleus.
- Atomic number is the number of protons present in the nucleus of every atom of that element. Mass number is the sum of protons and neutrons present in the nucleus of the atom. Protons and neutrons are collectively known as nucleons.
- The elements in the periodic table are arranged on the basis of their increasing atomic number, and the atomic number is equal to the number of protons present in the nucleus.
The number of protons in cobalt = 27
Number of protons in nickel = 28
- The mass of cobalt is higher due to the presence of different isotopes which have more number of neutrons.

Note: If we have to calculate the number of neutrons with the help of the given information, then the number of neutrons will be equal to the difference between the mass number of the atom and the atomic mass or the number of protons present in the atom. Mass number is the sum of protons and neutrons present in the nucleus of the atom. -Protons and neutrons are collectively known as nucleons and they are present inside the nucleus of the atom.