ICSE Class 6 Answered

• Elements are pure substances which are the basic unit of matter and cannot be broken down into two or more simpler substances by any means.

Occurrence of elements

• Elements are obtained both naturally and by artificial means.
• There are about 118 elements.
• Naturally occurring elements can be found in the Earth’s crust, atmosphere and also in living organisms.
• There exist elements having single atoms (K, Mg, Na, S, Ar), double atoms (O₂, H₂, N₂) and more than two atoms (O₃, P₄)

Elements are classified as follows-

• Metallic elements
• Non-metallic elements
• Metalloids
• Noble gases

An atom of any element is denoted by a ‘symbol’. A symbol is a short form or abbreviated name of the element.