NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 1: Number System - Problems and Solutions
Question 110

Question. 110

110. Science Application: An atom consists of electrons and protons. Each proton has charge +1 and each electron has charge −1. (Number of electrons = number of protons in a neutral atom.)

(a) What is the charge on an atom?

(b) What will be the charge on an atom if it loses an electron?

(c) What will be the charge on an atom if it gains an electron?

Answer:

(a) 0

(b) +1

(c) −1

Detailed Answer with Explanation:

(a) Equal numbers of +1 and −1 charges cancel.

(b) Losing one electron leaves one extra proton → net +1.

(c) Gaining one electron adds an extra −1 → net −1.

NCERT Exemplar Solutions Class 7 – Mathematics – Unit 1: Number System – Problems and Solutions | Detailed Answers