Matter and Chemical Formulae

The smallest unit of matter which can exist independently is called

• an atom

• a molecule

• a compound

• an element

The total number of known elements are

• 118

• 119

• 120

• 108

The chemical symbol for calcium is

• Ca

• Cl

• Cu

• Ce

The valency of hydroxide (OH) radical is

• 1

• 2

• 3

• 4

The number of atoms present in a molecule is called its

• atomicity

• valency

• symbol

• compound

An (a)   is a substance made of only one kind of atom.

The properties of a (a)   are different from its constituent elements.

(a)   is anything that has mass and occupies space.

The abbreviations used to represent elements are called (a)  

The arrow symbol in a chemical equation indicates the (a)   of the chemical reaction.