Chapter 4.3, Problem 21SSC

Interpretation Introduction

Interpretation:

Subatomic particle that identifies an atom as that of a particular element needs to be determined.

Concept introduction:

Atom is the smallest particle in the element that can neither be created nor be destroyed. It is composed of three subatomic particles, protons, neutrons and electrons.

Answer to Problem 21SSC

The subatomic particle proton identifies an atom of a particular element.

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, number of protons can identify an atom of a particular element.