Class 9 Science


Atoms

On the basis of Dalton’s Atomic Theory The smallest particles of matter are called Atoms.

Characteristics of atoms:

Symbols of Atoms of Elements

For the sake of convenience, elements are represented by unique symbols. For example: Hydrogen is represented by ‘H’.
Oxygen is represented ‘O’.
Nitrogen is represented by ‘N’.
Iron is represented by ‘Fe’.

Names and Symbols of some elements

ElementSymbol
HydrogenH
HeliumHe
LithiumLi
BerylliumBe
BoronB
CarbonC
NitrogenN
OxygenO
FluorineF
SodiumNa
MagnesiumMg
AluminiumAl
PhosphorousP
SulphurS
PotassiumK
CalciumCa

Symbols of many elements are taken from their English name, while symbols of many others are taken from their Greek or Latin names.

Symbols of some element which are derived from their Latin name

English nameSymbolLatin name
SodiumNaNatrium
PotassiumKKalium
IronFeFerrum
CopperCuCuprum
SilverAgArgentum
GoldAuAurum
MecuryHgHydragyrum
LeadPbPlumbum
TinSnStannum

Several elements are named after the place where they discovered. Example: Copper was discovered in Cyprus. Thus, it got its name similar to Cyprus.

Some elements are named after their colour. Example: Gold means yellow.

Quiz



See Answer

1: (a) Fe, 2: (c) Gold, 3: (d) Silver, 4: (c) Na, 5: (b) K, 6: (a) Pb, 7: (b) Sn, 8: (c) Mercury, 9: (d) Natrium, 10: (a) Kalium