Families and groups of the periodic table explained

The groups of the periodic table are the vertical columns, numbered 1 to 18. Elements in the same group have the same number of valence electrons, which explains why they react in similar ways. Knowing the main families makes it easy to predict the behavior of many elements at once.

Alkali metals (Group 1)

Lithium, sodium, potassium and company are soft, extremely reactive metals that react vigorously with water. They have a single valence electron, which they lose easily to form ions with a +1 charge.

Alkaline earth metals (Group 2)

Beryllium, magnesium, calcium and others are reactive, but less so than the alkalis. They have two valence electrons and form +2 ions. Calcium and magnesium are essential to living organisms.

Halogens (Group 17)

Fluorine, chlorine, bromine and iodine are very reactive non-metals that tend to gain one electron to form -1 ions. They are known for forming salts with metals.

Noble gases (Group 18)

Helium, neon, argon and the rest have a complete valence shell, which makes them chemically stable and barely reactive. That's why they are used in lighting, welding and inert environments.

At the center of the table sit the transition metals (groups 3 to 12), and at the bottom the lanthanides and actinides, from the f-block. Mastering the families is the shortcut to understanding chemistry without memorizing each element in isolation.