Question

‘The modern periodic table consists of elements arranged according to their increasing atomic numbers’. With reference to elements with atomic numbers 1 to 20 only in the periodic table – differentiate them into – metallic elements, metalloids, non-metals & noble gases.

Answer 1

Names and symbols of metal, non-metals, metalloids, and noble – gases out of 1st 20 elements.

Metal	Symbol	Non-metal	Symbol
Lithium	Li	Hydrogen	H
Beryllium	Be	Carbon	C
Sodium	Na	Nitrogen	N
Magnesium	Mg	Oxygen	O
Aluminium	Al	Fluorine	F
Potassium	K	Phosphorus	P
Calcium	Ca	Sulphur	S
		Chlorine	Cl

Metalloids	Symbol	Noble gas	Symbol
Boron	B	Helium	He
Silicon	Si	Neon	Ne
		Argon	Ar