MATTER

 MATTER OCCUPIES SPACE AND HAS A MASS

THE CHEMICAL ELEMENTS

A chemical element is a pure substance that cannot be divided or changed into different substances by ordinary chemical methods.

STRUCTURE OF ATOMS

An atom defined as the smallest part of a chemical element that retains the identity of the element.

• Around the nucleus, small charged particles called electrons move in complicated patterns called orbitals.
• The outer-most orbitals shell of any atom's electrons is called the valence shell.
• The number of electrons in the valence shell determines the chemical bonding properties of the material as well as other characteristics such as conductivity.
• Two or more substances may share the electrons in their valence shell and form a covalent  bond.

ISOTOPES

When atoms of the same element have different number of neutrons, they are called isotopes.

• Same in chemically
• Different in physically (because of different mass)

MOLECULES

Molecules is the smallest structural unit of a substances that has all the physical and chemical properties of that substance.

STATES OF MATTER