Atomic Symbol
Element Name
Atomic Mass
Periods & Groups
# of Protons
100

Sodium

Na

100

Na

Sodium


100

12.001

Carbon
100

p1 g1

Hydrogen
100

Carbon

6

200

Potassium

K

200

Mn

Manganese

200

1

Hydrogen

200

p3 g15

Phosphorous 

200
Cromium 

24

300

Flourine

F


300

Br

Bromine

300

15.999

Oxygen 

300

p6 g11

Gold


300

Barium 

56

400

Silver 

Ag


400

Pb

Lead


400

226

Radium 

400

g18 p5

Xe

400

Curium 

96

500

Tungsten

W


500

Hg

Mercury

500

168.93

Thulium

500

g17 p4

Bromine

500

Polonium

84