The modern periodic table

In the modern periodic table:

  • elements are arranged in rows, called periods, in order of increasing atomic number
  • elements with similar properties are placed in vertical columns, called groups
  • elements in the same group have the same number of electrons in their outer shell (this is what gives them similar properties)

The table is called the periodic table because elements with similar properties occur at regular intervals.

Periodic table with group and period numbers labelledThe modern periodic table with some elements left out for simplicity

Remember that the periodic table only lists elements, so you won't find compounds (eg water) or alloys, eg bronze listed there.