21
Scandium - Sc
20
Calcium - Ca
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
31
Gallium - Ga
32
Germanium - Ge
33
Arsenic - As
34
Selenium - Se
35
Bromine - Br
36
Krypton - Kr
37
Rubidium - Rb
38
Strontium - Sr
39
Yttrium - Y
40
Zirconium - Zr
41
Niobium - Nb
42
Molybdenum - Mo
43
Technetium - Tc