what is a group on the periodic table

A group on the periodic table is a vertical column of elements whose atoms have the same number of valence (outer-shell) electrons, so they show very similar chemical and physical properties.

Quick Scoop: What Is a Group?

• A group is a vertical column on the periodic table, not a row.

• All elements in one group have the same number of valence electrons, which largely controls how they react.

• Because of this, group members tend to have similar properties (for example, similar reactivity, forming similar types of compounds).

• Modern tables use group numbers 1 to 18, running from left to right.

Think of a group like a “family” of elements: different individuals, but the same basic personality because their outer electrons are arranged in a similar way.

A Bit More Detail

• In many sources, “group” and “family” are used almost interchangeably for these columns.

• Famous examples:
  • Group 1: alkali metals (plus hydrogen), very reactive, 1 valence electron.

* Group 17: halogens, very reactive nonmetals, 7 valence electrons.

* Group 18: noble gases, very unreactive, full valence shells.

• The pattern of repeating properties down a group is one of the key reasons the periodic table is “periodic” at all.

In short: a group is a vertical column on the periodic table whose elements share the same number of outer electrons and therefore behave in similar ways.

Information gathered from public forums or data available on the internet and portrayed here.