Question

An atom of an element contains 13 electrons. Its nucleus has 14 neutrons. Find out its atomic number and approximate atomic mass. An isotope has atomic mass 2 units higher. What will be the number of protons, neutrons and electrons in the isotope?

Answer 1

Hint: Isotopes of an element are variants of an element which have the same number of protons and electrons thus the atomic number is the same. The changes come when we talk about the neutrons. Isotopes have different neutrons thus there is a difference in the atomic mass. Alternately, isotopes can be defined as variants of elements that differ in their nucleon numbers due to a difference in the total number of neutrons in their respective nuclei.

Complete step-by-step answer:
Atoms and elements are made of protons, neutrons and electrons. The nucleus is made of protons and neutrons, and the electrons surround the nucleus. The sum of the number of protons and the number of neutrons is equal to the atomic mass.
When we talk about the applications of isotopes we must remember that it can be used in the determination of the isotopic signature of element samples via isotope analysis. This is generally done via the process of isotope ratio mass spectrometry.
Isotopes can also be used to determine the concentration of many elements/substances via isotope dilution.

Atomic number=No. of protons=No. of electrons in ground state(unchanged atom)
Atomic number\[ = 13 = No.{\text{ }}of{\text{ }}protons\]
Atomic mass\[ = no.{\text{ }}of{\text{ }}protons + no.{\text{ }}of{\text{ }}neutrons = 13 + 14 = 27\]
For isotope no. of proton=\[13\] (same atomic number but different mass number are isotopes)
No. of electrons=\[13\]
No. of neutrons=\[14 + 2 = 16\]

Note: Since the atomic number is equal to the number of protons and the atomic mass is the sum of protons and neutrons, we can also say that isotopes are elements with the same atomic number but different mass numbers. Some isotopes of some elements and these isotopes are called radioactive isotopes.