4. periode
Kalium
19
Calcium
20
Scandium
21
Titan
22
Vanadium
23
Krom
24
Mangan
25
Jern
26
Kobolt
27
Nikkel
28
Kobber
29
Zink
30
Gallium
31
Germanium
32
Arsen
33
Selenium
34
Brom
35
Krypton
36
Periodisk System
Sprog
Hent