Question

What is the relation between the number of protons and the number of electrons in an atom?

Answer 1

• Electron is a negatively charged particle revolving around the nucleus in a fixed path known as its orbit.
• Electron was discovered by J.J.Thomson in the year 1897.
• Proton is a subatomic particle having a positive charge on it present in the nucleus of an atom.
• It was discovered by Eugen Goldstein in the year 1920.

Relation between the number of protons and the number of electrons in an atom-

(i) Number of Electron = Number of protons

• A neutral atom has an equal number of electrons and protons.
• For example, Hydrogen has 1 electron and 1 proton and its atomic number is 1.

(ii) Number of Electron > Number of protons

• When an atom gains an electron it has more electrons than the proton.
• It acquires a negative charge and forms anion.
• Generally, this tendency is shown by non-metals.
• For example, Chlorine(Cl) has 17 protons and 17 electrons.
• Chlorine gains an electron to form ${\mathrm{Cl}}^{-}$ ion.

(iii) Number of Electron < Number of protons

• When an atom loses an electron it has fewer electrons than the proton.
• It acquires a positive charge and forms a cation.
• Generally, this tendency is shown by metals.
• For example, Sodium(Na) is a metal having the atomic number 11.
• It has 11 electrons and 11 protons in its atom.
• Sodium loses an electron to form ${\mathrm{Na}}^{+}$ion.