Principal Quantum number (level)

The name of the period

Number of revolutions

Number of elements

The elements

1

0

0

2

1-Hydrogen, 2-Helium

2

A

1

8

3-Lithium … 10-Neon

3

A

1

8

11-Sodium …18-Agon

4

A + B

2

18

19-potassium…36-Krypton

5

A + B

2

18

37-Rubidium …54-Xenon

6

A + B + C

4

32

55-Cesium …. 86-Radon

7

A + B + D

4

32

87Francium…118-Oganesson