Write isotopic symbols in the form ^A_ZX for each isotope. c. the potassium isotope with 21 neutrons

Key Concepts

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This difference in neutron count results in varying atomic masses for the isotopes of the same element. For example, potassium has several isotopes, including potassium-39 and potassium-40, which differ in their neutron numbers.

Isotopic Notation

Isotopic notation is a way to represent isotopes using the format AZX, where 'A' is the mass number (total number of protons and neutrons), 'Z' is the atomic number (number of protons), and 'X' is the chemical symbol of the element. For potassium, which has an atomic number of 19, the notation for an isotope with 21 neutrons would be written as 40K, since the mass number (A) is 19 protons + 21 neutrons = 40.

Mass Number

The mass number of an isotope is the sum of the number of protons and neutrons in its nucleus. It is a crucial factor in isotopic notation and helps distinguish between different isotopes of the same element. In the case of potassium with 21 neutrons, the mass number would be 40, indicating that it has 19 protons and 21 neutrons.