Question

The table given below is made on the basis of the modern periodic table. Write in it the electronic configuration of the first 20 elements below the symbol, and write the valency (as shown in a separate box).

Symbol Electronic configuration Valency

19K 2, 8, 8, 1 1

Answer 1

↓	1	2	13	14	15	16	17	18
1	H 1							He 2 0
2	Li 2, 1 1	Be 2, 2 2	B 2, 3 3	C 2, 4 4	N 2, 5 3	O 2, 6 2	F 2, 7 1	Ne 2, 8 0
3	Na 2, 8, 1 1	Mg 2, 8, 2 2	Al 2, 8, 3 3	Si 2, 8, 4 4	P 2, 8, 5 3	S 2, 8, 6 2	Cl 2, 8, 7 1	Ar 2, 8, 8 0
4	K 2, 8, 8 1	Ca 2, 8, 8, 2 2