Atomic Structure of Isotopes

A similar atomic number but a different mass number is a characteristic of isotopes. The structure of an atom is known as the atomic structure. The atom consists of three types of subatomic particles: protons (positively charged), neutrons (no charge) and electrons (negatively charged). The nucleus of the atom is made up of positively charged protons and neutrons, which are neutral, while the negatively charged electrons move around it in circular orbits. The total number of protons in the nucleus is the atomic number of that element. The mass number is the sum of the total number of protons and the total number of neutrons in an atom.

History

• In the 1800s, scientist John Dalton proposed Dalton’s atomic theory, where he stated the properties of atoms: all matter is made up of atoms; atoms are indivisible units; a particular element has a similar type of atoms; atoms can neither be created nor be destroyed – they can just undergo rearrangements.
• In the 1900s, J.J. Thomson discovered electrons and gave us the famous plum-pudding model.
• Then Rutherford discovered that the central part of an atom is positively charged and named it the nucleus. He also put forward the theory that electrons are negatively charged particles and move around the nucleus in orbits.
• Then came Bohr’s model of atoms.

Basics

• Total number of protons = Atomic number (Z)

• Isotopes of an element have the same number of protons but different neutrons.
• Mass number (A) = number of protons + number of neutrons.
• The number of protons = number of electrons

Atomic Structure of Isotopes

• Atomic structure is the structure of an atom.
• Isotopes are types of an atom that have the same number of protons and a different number of neutrons.
• The difference in the number of neutrons changes the atomic mass of the isotopes of the element.
• In other words, isotopes of an element have the same atomic number (Z) but different mass number (A).
• Hence the isotopes of an element are placed in the same respective position as that of the original element in the periodic table.
•  The isotopes of an element have the same electronic configuration as the atomic number is the same.
• The isotopes of an element show similar chemical properties because the electron determines the chemical behaviour of an element. In isotopes, the number of electrons remains the same; hence they show similar chemical properties.

Examples of different isotopes and their atomic structure

• Isotopes of hydrogen are Protium, Deuterium and Tritium.

Protium contains 1 proton + 1 electron. The atomic number is 1, and the mass number is also 1.

Deuterium contains 1 proton + 1 neutron. The atomic number is 1, but the mass number is 2 in this case.

Tritium contains 1 proton + 2 neutron. The atomic number is 1, but the mass number is 3.

• Isotopes of carbon are ¹²C, ¹³C and ¹⁴C. Out of these, ¹²C is the most common isotope of carbon.

¹²C contains 6 neutrons and 6 protons. It has an atomic number 6, whereas the mass number is 12.

¹³C contains 7 neutrons and 6 protons. The atomic number is 6, whereas the mass number is 13.

¹⁴C has 8 neutrons and 6 protons. The atomic number is 6, and the mass number is 14.

• Isotopes of oxygen are ¹⁶O, ¹⁷O and ¹⁸O. Out of these, 16O is the most common.

¹⁶O contains 8 protons and 8 neutrons. The atomic number is 8, but the mass number is 16.

¹⁷O contains 8 protons and 9 neutrons. The atomic number here is 8, but the mass number is 17.

¹⁸O contains 8 protons and 10 neutrons. The atomic number is 8, while the mass number is 18.

Benefits of Isotopes

• Radioactive isotopes are useful in agriculture, the food industry, archaeology and medicine.
• Isotopes of carbon are used in carbon dating and the study of fossils.
• Few isotopes also have great importance in determining the biological processes happening in the human body.
• It can also be used to diagnose different diseases.

Conclusion

Atomic structure is defined as the structure of an atom. The atom consists of three types of subatomic particles. The three subatomic particles are protons (positively charged), neutrons (no charge or neutral) and electrons (negatively charged). The atomic structure of isotopes is different, as the mass number of Isotopes are different. The electronic configuration of isotopes is the same, as the atomic number of isotopes are the same. Hence, mass numbers and atomic numbers play a very important role in determining the position and behaviour of an atom. The isotopes of an element are also known for various uses in different industries.