Chapter 8, Problem 1STP

Summary Introduction

Introduction:

Matter is anything that has mass and takes up space. It is made up of small units called atoms. An atom is made up of still smaller particles called electrons, protons and neutrons. Elements are made of same kind of atoms.

Answer to Problem 1STP

Correct answer :

The correct answer is option (A),neutrons.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A), neutrons. Isotopes are atoms of same element having same number of protons and electrons but different number of neutrons. The given element X-97 and X-99 are isotopes. So they differ in the number of neutrons. X-99 has 2 neutrons more than X-97. Hence, this is the correct option.

Explanation for incorrect answer:

Option (B),protons.Isotopes are atoms of same element having same number of protons and electrons but different number of neutrons. The given element X-97 and X-99 are isotopes. So they have same number of protons. Hence, this is not the correct option.

Option (C)orbiting electrons. Isotopes are atoms of same element having same number of protons and electrons but different number of neutrons. The given element X-97 and X-99 are isotopes. So they have same number of electrons. Hence, this is not the correct option.

Option (D)overall charge.Isotopes are atoms of same element having same number of protons and electrons but different number of neutrons. The given element X-97 and X-99 are isotopes. So, they have same number of electrons and protons; hence, the overall charge is also same. Hence, this is not the correct option.