Chapter 4.3, Problem 20SSC

Interpretation Introduction

Interpretation:

The basis on which an atom can be defined needs to be explained.

Concept introduction:

Atom is the smallest particle in the element that can neither be created nor destroyed.

Answer to Problem 20SSC

The type of an atom is defined by its atomic number.

Explanation of Solution

An atom is defined on the basis of an atomic number. It is discovered by the scientist that in an element there are atoms with unique positive charge. This positive charge is due to positively charged particles known as protons present in the nucleus of an atom. Hence, the number of protons in an atom identifies it as an atom of a particular element.

For example: An atom has 7 protons, so its atomic number is 7, now according to modern periodic table the element with atomic number 7 is Nitrogen. Thus, the atom is of element-Nitrogen.

Conclusion

Hence, by the atomic number, the type of an atom is defined.