Question

write down 1upto 20 th elements with their symbols and atomic number according to the increasing order of their atomic number​

Answer 1

These are the first 20 elements, listed in order:

H - Hydrogen

He - Helium

Li - Lithium

Be - Beryllium

B - Boron

C - Carbon

N - Nitrogen

O - Oxygen

F - Fluorine

Ne - Neon

Na - Sodium

Mg - Magnesium

Al - Aluminum

Si - Silicon

P - Phosphorus

S - Sulfur

Cl - Chlorine

Ar - Argon

K - Potassium

Ca - Calcium