hydrogen atom

1

atomic numberso one electron

1 HX

helium atom

2

atomic numberso two electrons

2HeXX

lithium atom

3

atomic numberso three electrons

2 , 1Li X

XX

beryllium atom

4

atomic numberso four electrons

2 , 2BeXX

XX

boron atom

5

atomic numberso five electrons

2 , 3 BXX

XX

X

carbon atom

6

atomic numberso six electrons

2 , 4 CXX

XX

XX

nitrogen atom

7

atomic numberso seven electrons

2 , 5 NXX

XX

XX

X

oxygen atom

8

atomic numberso eight electrons

2 , 6 OXX

XX

XX

XX

fluorine atom

9

atomic numberso nine electrons

2 , 7 FXX

XX

XX

XX

X

neon atom

10

atomic numberso ten electrons

2 , 8NeXX

XX

XX

XX

XX

sodium atom

11

atomic numberso eleven electrons

2 , 1, 8Na

X

XX

XX

XX

XX

XX

magnesium atom

12

atomic numberso twelve electrons

2 , 2, 8MgXX

XX

XX

XX

XX

XX

aluminium atom

13

atomic numberso thirteen electrons

2 , 3, 8AlXX

XX

XX

XX

XX

XX

X

silicon atom

14

atomic numberso fourteen electrons

2 , 4, 8SiXX

XX

XX

XX

XX

XX

XX

phosphorus atom

15

atomic numberso fifteen electrons

2 , 5, 8 PXX

XX

XX

XX

XX

XX

XX

X

sulphur atom

16

atomic numberso sixteen electrons

2 , 6, 8 SXX

XX

XX

XX

XX

XX

XX

XX

chlorine atom

17

atomic numberso seventeen electrons

2 , 7, 8 ClXX

XX

XX

XX

XX

XX

XX

XX

X

argon atom

18

atomic numberso eighteen electrons

2 , 8, 8 ArXX

XX

XX

XX

XX

XX

XX

XX

XX

potassium atom

19

atomic numberso nineteen electrons

2 , 8, 8 KXX

XX

XX

XX

XX

XX

XX

XX

XX

, 1

X

calcium atom

20

atomic numberso twenty electrons

2 , 8, 8CaXX

XX

XX

XX

XX

XX

XX

XX

XX

, 2

XX