Atomic Number & Mass Number

Number of Electrons

100

Silicon

14

200

Phosphorus

15

300

Iron

26

400

Iodine

53

500

Cesium

55

Atomic Number

100

Scandium

21

200

Zinc

30

300

Selenium

34

400

Silver

47

500

Gold

79

Atomic Mass

100

Calcium

40.078

200

Manganese

54.938

300

Cobalt

58.933

400

Fluorine

18.998

500

Uranium

238.03

Mass Number

100

p⁺=18.   n^o=22

40

200

p⁺=14.   n^o=15

29

300

p⁺=21.   n^o=24

45

400

p⁺=74.   n^o=109

183

500

p⁺=82.   n^o=125

207

Number of Protons

100

Aluminum

13

200

Potassium

19

300

Titanium

22

400

Xenon

54

500

Barium

56