Chapter 2, Problem 1MCQ

Summary Introduction

Introduction:

Centre of the atom consists of dense nucleus formed with protons and neutrons, the subatomic particles which are surrounded by electrons. Each proton that is present in the nucleus of atom carries positive charge and neutron carries no charge. The charge on each electron surrounding nucleus is negative. An atom’s mass number is the total number of neutrons and protons present in its nucleus.

Answer to Problem 1MCQ

Correct answer:

A $\text{carbon}-\text{14}$ has 8 neutrons, 6 protons, and 14 mass number. Therefore, option a. is correct.

Explanation of Solution

Reason for the correct statement:

Option a. is given as “ $8;6;14$”. The mass number of $\text{carbon}-\text{14}$ is 14 which refers to a number of neutrons and protons in the carbon atom. A number of protons always remains same in each isotope of an element. Thus $\text{carbon}-\text{14}$ have 6 protons which mean it there have to be 8 neutrons. Hence, A $\text{carbon}-\text{14}$ has 6 protons, 8 neutrons and a mass number of 14.

Hence, option a. is correct.

Reasons for the incorrect statements:

Option b. is given as “ $6;8;14$”. All the carbon atoms have 6 protons. Hence, option a. is incorrect.

Option c. is given as “ $7;7;14$”. All the carbon atoms have 6 protons in their nucleus. Hence, option c. is incorrect.

Option d. is given as “ $8;6;12$”. An isotope  $\text{carbon}-\text{12}$ has mass number 12 with 6 protons and neutrons. Hence, option d. is incorrect.

Hence, options b., c., and d. are incorrect.

Conclusion

A $\text{carbon}-\text{14}$ has a mass number of 14 and 6 protons and 8 neutrons in nucleus.