The chemical elements are arranged into rows (horizontal) and columns (vertical). The columns are called groups, and the elements contained within each group generally have the same number of valence electrons (there are some exceptions in the transition metals). This means elements within a group have have similar properties in the types of chemical bonds the create. Lithium, sodium, and potassium and some other elements form the first group of the periodic table which all contain one valence electron (marked purple in the image below).

Main groups

Group 1-2 and 13-18 are called main groups, and have specific names. In the table below you see the names of the main groups, and the main characteristics of those groups.





1. Alkali metals


Light, soft metals which easily reacts with other elements to donate away their single valence electron.

Lithium, sodium, potassium

2. Alkaline earth metals


Approximately the same as group 1. Some elements are common in the earth crust.

Magnesium, calcium

13. Boron
3 Generally non-reactive and have metal properties. Often creates oxides. Boron, aluminum

14. Carbon


Can create 4 covalent bonds. Very important in living organisms.

Carbon, silicon

15. Nitrogen family


Can create 3 covalent bonds.

Nitrogen, phosphorus

16. Oxygen family


Many of these chemical elements creates minerals in the presence of metals.

Oxygen, sulphur

17. Halogens


Often takes up an electron to reach a noble gas shell. Easily forms salts. Sticks together two and two with atoms from the same group.

Fluorine, chlorine, bromine, iodine

18. Noble gases

(2 in the case of helium)

Doesn't react easily with other elements.

Helium, neon, argon

As you might notice, the number of valence electrons are identical to the last single digit of the group. This is true only for the groups 1-2 and 11-18.

Transition metals

The chemical elements of group 3-12 are called transition metals (or transition elements). They generally have 1-2 valence electrons. Their second outermost shell is partially filled, and is gradually filled the longer to the right we go within the periodic table.

You can now either read more about group 1 and group 2, or learn more about periods.

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