Upon completion of this lesson, student must be able to:

  • Define elements, compound, atoms and molecules.
  • Give a brief description on structure of atom.
  • Define and differentiate atomic number and atomic mass.
  • Know the distribution of electrons in shell.
  • Draw atomic structures.
  • Solve numerical related to atomic mass and atomic number.
  • Classify elements according to periodic function of their atomic mass and number.


Electronic Configuration and Atomic Structure

The distribution of electrons in the various shells of atom is known as the electron configuration. There are different ways to write electronic configuration. This note explains what is electronic configuration and how to write it.

Classification of Elements

Classification of elements: The main utility of the system is that it affords a scheme of classification of elements, which is helpful in the study of 109 elements is reduced to nine groups only. This note provides an information about elements.

Introduction to Matter

A substance which cannot be further broken down into other simpler substances is called an element. Hydrogen, oxygen, nitrogen, chlorine, mercury, lead, etc. are the examples of the element. This note provides further information about the matter.

Structure of Atom

Sub-atomic particles of atoms are the particles that make up the atom. There are three fundamental sub-atomic particles: Electron, Proton and Neutron. This note provides information about sub- atomic constituents of an atom.

Molecular Properties

Molecule combines together to from a substance. In this way, a substance is formed by atoms. This note provides further information about atomic properties of an element.

Valency, Molecular Formula and Chemical Reaction

The combining capacity of elements or the radicals with the other elements or radicals to form the molecule of an element or compound is called valency. This note provides us an information about valency, molecular formula and chemical reaction.