Write atomic number of first 20 elements
1 Hydrogen H 1
2 Helium He 2
3 Lithium Li 3
4 Beryllium Be 4
5 Boron B 5
6 Carbon C 6
7 Nitrogen N 7
8 Oxygen O 8
9 Fluorine F 9
10 Neon Ne 10
11 Sodium Na 11
12 Magnesium Mg 12
13 Aluminium Al 13
14 Silicon Si 14
15 Phosphorus P 15
16 Sulfur S 16
17 Chlorine Cl 17
18 Argon Ar 18
19 Potassium K 19
20 Calcium Ca 20
Write atomic number and atomic masses of first 20 elements of periodic table
1 Hydrogen H 1
2 Helium He 4
3 Lithium Li 6
4 Beryllium Be 9
5 Boron B 11
6 Carbon C 12
7 Nitrogen N 14
8 Oxygen O 16
9 Fluorine F 19
10 Neon Ne 20
11 Sodium Na 23
12 Magnesium Mg 24
13 Aluminium Al 27
14 Silicon Si 28
15 Phosphorus P 31
16 Sulfur S 32
17 Chlorine Cl 35.5
18 Argon Ar 40
19 Potassium K 39
20 Calcium Ca 40 ;
21 Scandium Sc
22 Titanium Ti
23 Vanadium V
24 Chromium Cr
25 Manganese Mn
26 Iron Fe
27 Cobalt Co
28 Nickel Ni
29 Copper Cu
30 Zinc Zn Cations
Hydrogen ion H⁺
Sodium ion Na⁺
Potassium ion K⁺
Silver ion Ag⁺
Copper(I) ion Cu⁺
Magnesium ion Mg²⁺
Calcium ion Ca²⁺
Zinc ion Zn²⁺
Iron(II) ion Fe²⁺
Iron(III) ion Fe³⁺
Aluminium ion Al³⁺
Ammonium ion NH₄⁺
Anions
Chloride ion Cl⁻
Fluoride ion F⁻
Bromide ion Br⁻
Iodide ion I⁻
Oxide ion O²⁻
Sulphide ion S²⁻
Nitride ion N³⁻
Hydroxide ion OH⁻
Nitrate ion NO₃⁻
Nitrite ion NO₂⁻
Sulphate ion SO₄²⁻
Sulphite ion SO₃²⁻
Carbonate ion CO₃²⁻
Bicarbonate (hydrogen carbonate) ion HCO₃⁻
Phosphate ion PO₄³⁻
Acetate ion CH₃COO⁻