Question

write down the name of elements and their symbols up to 20 with electronic configuration and valency of 20 element​

Answer 1

Answer:

hydrogen -1

helium 2

lithium2,1

beryllium 2,2

boron 2,3

carbon 2,4

nitrogen 2,5

oxygen 2,6

flourine 2,7

neon 2,8

sodium 2,8,1

magnesium 2,8,2

aluminuim2,8,3

silicon 2,8,4

Phosphorus 2,8 5

Sulphur 2,8,6

chlorine 2,8,7

argon 2,8,8

potassium 2,8,8,1

calcium 2,8,8,2

Explanation:

valencies are the last number at the end of the configuration