Question

What is an Isotone, isobar and isodiaphers

Answer 1

Isotopes are atoms with the same number of protons but that have a different number of neutrons. 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.

Atoms and elements are made of protons, neutrons and electrons. The nucleus is made of protons and neutrons, and the electrons surround the nucleus, as shown in the illustration below. The sum of the number of protons and the number of neutrons is equal to the atomic mass.

Isobars are atoms of different Chemical elements that have the same number of nucleons. Correspondingly, isobars differ in atomic number (or number of proton) but have the same mass number. An example of a series of isobars would be

The nuclei of these nuclides all contain 40 nucleons; however, they contain varying numbers of protons and neutrons. The term "isobars" (originally "isobares") for nuclides was suggested by Alfred in 1918. It is derived from the Greekword isos, meaning "equal" and baros, meaning "weight".

Isotone, any of two or more species of atoms or nuclei that have the same number of neutrons. Thus, chlorine-37 and potassium-39 are isotones, because the nucleus of this species of chlorine consists of 17 protons and 20 neutrons, whereas the nucleus of this species of potassium contains 19 protons and 20 neutrons.

Isodiaphers are sets of nuclides which may have different numbers of protons or neutrons, but have the same difference between the number of protons and neutrons i.e. neutron excess.

For example Thorium-234 and Uranium-238 are isodiaphers.

For Thorium-234, number of protons = 90, number of neutrons =144, hence neutron excess is 54

For Uranium-238, number of protons = 92, number of neutrons = 146, hence neutron excess is again 54.