What is Isobar isotope isotone and how to differentiate them

Isobar isotope isotone isoelectronic species

What are isobar isotope isotone isoelectronic species

Here in this article you will learn about isobar isotope isotone isoelectronic species with different examples. You will also learn about isobar isotope isotone isoelectronic species with the help of notes and video given below.

What are isotopes ?

Atoms of the same element  having same atomic number but different mass number are called as isotopes. Therefore isotopes are having same chemical properties but different physical characteristics.

Sometimes atoms of the same element contain the same number of protons but different number of neutrons. Consequently, they have same atomic number but different mass number.

As we know,

Atomic number of an element = total number of protons present in the nucleus = total number of electrons present in the neutral atom

Mass number of an element = Number of protons + number of neutrons

The atoms of same element having same atomic number but different mass numbers are called as isotopes.

Examples of isotopes

There are three isotopes of hydrogen having mass numbers 1, 2 and 3 respectively having atomic number equal to 1. Isotopes of hydrogen are represented as 1H, 2H, 3H and are named as protium, deuterium, and tritium. 

Ordinary hydrogen is known as protium. Isotopes of other elements or not having any special names. For example isotopes of chlorine are represented as 35Cl and 37 Cl. Therefore Chlorine is found to have two isotopes having same atomic number 17 but different mass numbers 35 and 37

Types of isotopes

There are mainly two types of isotopes known as radioactive isotopes and stable isotopes. Stable isotopes have stable combination of protons and neutrons so they do not undergo any decay. Hence, stable isotopes do not cause any dangerous effects to living things  unlike radioactive isotopes.

Radioactive  isotopes have unstable combination of protons and neutrons so, they undergo decay because of unstable nuclei. In the process of decay radioactive isotopes emit alpha, beta and gamma rays.

Uses of isotopes

Isotopes  are widely used in medicine, agricultural sector and industrial sector.

For example carbon 14 is used to estimate the age of fossils or in wood by measuring the fraction of carbon 14  that has been left.

What are isobars ?

Some atoms of different elements have same mass number but different atomic number. Therefore, electronic configuration of isobars are different.

 Calculation of number of neutrons, protons and electrons

Number of electrons = Number of protons = atomic number

As we know, Number of protons + Number of neutrons = mass number

Number of protons = Mass number – Number of neutrons

Also, Number of neutrons = Mass number – Atomic number

So, atoms of different elements having different atomic numbers but same mass numbers are called as isobars 

Examples of isobars

So in all these species, 18Ar, 19K, 20Ca  or

Argon Potassium and Calcium are having different atomic numbers 18,19, and 20 but having same mass number 40 

Uses of isobars

Uranium isobars are used in nuclear reactors, cobalt isobars are used for cancer treatment and iodine isobars are used in goitre treatment

You can watch all the related videos from  the structure of atom from the given playlist:

structure of atom 

What are isotones ?

Such atoms of different elements having same number of neutrons are called is isotones. For example carbon, nitrogen and oxygen differ in the atomic number as well as in mass number but are having same 8 neutrons.

Examples of isotones

 3616S, 3717Cl, 3818Ar, 3919K, and 4020Ca are all isotones since they all contain 20 neutrons.

2. Consider the second example of isotone :

Chlorine-37 and Potassium-39 

Chlorine (Cl) having atomic number 17

Number of protons  = 17

And No of neutrons = 37 – 17 = 20

Potassium (K) having atomic number 19

Number of protons = 19

So, Number of neutrons = 39- 19 = 20

Therefore, Cl and K are regarded as isotones

What are isoelectronic species?

Ions of the different elements having same number of electrons by different nuclear charge or called as isoelectronic species.

N3–, O2–, F–, Ne, Na+, Mg2+, and Al3+ all are having same number of electrons.


What are isotopes

Define isotopes and isobars.

What are isotopes and isobars give examples

Define isotopes give example

What are isotopes isobars and Isotones

Check out the structure of NH3 here

For more updates join me on 

You Tube Channel :

Chemistry with mona mam

Website :

 Basics of chemistry.com



Basics OF Chemistry

Let's Build chemistry with Chemistry !

Leave a comment