Basic Chemistry: Electrons, Protons And Neutrons, Electrons Are Important for Several Reasons

Get unlimited access to the best preparation resource for UGC : Get detailed illustrated notes covering entire syllabus: point-by-point for high retention.

Loading video

Basic Chemistry: Electron and Proton (Chemistry)

Table of Contents

  • Introduction

  • Atoms and Elements

  • Atomic number and atomic mass

  • Periodic Table and Chemical Bonds

  • Isotopes

  • Radioisotopes

  • Periodic Table and Chemical Bonds

  • Electronegativity

  • Chemical Bond

  • Compound, substance, Molecule

  • Acidity and Basicity

  • Redox Reaction

Learning Outcomes

After studying this lesson, you shall be able to: Electron and Proton

Electrons Electrons

Carbon Atom

Loading image


  • Electrons are small components which revolve around the nucleus. Electron has a negative charge.

  • An atom with no net electrical charge has the same number of electrons and protons.

  • Electrons are restricted to certain energy levels i.e. “shells” and orbitals within those energy levels.

  • These energy levels and orbitals fill in a regular pattern from the lowest energy level outward.

  • Here is an illustration of the orbitals of a Helium atom’s outer energy level.

Helium Atom

Helium Atom

Loading image

Helium Atom Electrons, Protons and Neutrons

Electrons Are Important for Several Reasons

  • Chemical bonds are formed when electrons are transferred or shared between atoms.

  • The arrangement of electrons in the atom of an element helps to determine the chemical properties of an element.

  • For example, when the outer most energy level of an atom is almost empty, the atoms of the element tend to give up electrons.

Chemical bonds

Chemical Bonds

Loading image
  • A good example is sodium.

  • When the outermost energy level of an atom is almost (but not completely) full, the atoms of the element tend to grab electrons from other atoms.

  • A good example is chlorine.


Example of Sodium

Loading image

Example of Chlorine

Loading image
  • Finally, electrons can carry and store energy and this is important in understanding metabolism.

  • Every time a chemical reaction takes place, electrons are shared or transferred between atoms and hence energy is shared or transferred.

  • For example, in photosynthesis light energy is captured and stored by electrons.

  • Then the electrons are used to make glucose, and other organic molecules which store the energy as potential energy in their chemical bonds.


  • The proton is a subatomic particle with the symbol p or p+ and a positive electric charge of 1 elementary charge.

  • One or more protons are present in the nucleus of each atom, along with neutrons.

  • The number of protons in each atom is its atomic number.


The Number of Protons

Loading image
  • The name proton was given to the hydrogen nucleus by Ernest Rutherford in 1920, because in previous years he had discovered that

  • the hydrogen nucleus (known to be the lightest nucleus) could be extracted from the nuclei of nitrogen and was thus a candidate to be a fundamental particle and building block of all complex atomic nuclei.


1. How many protons are present in Helium atom?

  1. 3

  2. 2

  3. 1

  4. 4

Answer: B. 2

2. Which among the following is a lightest nucleus?

  1. Hydrogen nucleus

  2. Oxygen nucleus

  3. Nitrogen nucleus

  4. Helium nucleus

Answer: A. Hydrogen nucleus