Chapter 4, Problem 62A

Interpretation Introduction

Interpretation:

The superscript and subscript in the notation $\text{K}$ needs to be described.

Concept introduction:

Mass number is the total number of protons and neutrons present in the nucleus of an atom. Atomic number is also referred as number of protons in an atom.

Answer to Problem 62A

$\text{K}$

Superscript in given notation represents Mass number

$\text{Mass number = 40}$

Subscript in given notation represents Atomic number

$\text{Atomic number = 19}$

Explanation of Solution

The symbol for an atom is represented as follows:

$\text{X}$

A − Mass number

Z − Atomic number

Therefore,

In $\text{K}$

Superscript represents Mass number

$\therefore \text{Mass number = 40}$

Subscript represents Atomic number

$\therefore \text{Atomic number = 19}$

Conclusion

In chemical symbol of an element superscript represents Mass number and subscript represents Atomic number