The Periodic Table

There are about 100 elements in the world.

The elements are arranged in a table. The table is known as the periodic table.

Going across the rows of the periodic table, atomic weights increase.

The columns of the periodic table contain elements with similar chemical properties.​​​

The periodic table has seven rows.

The numbers of elements in the seven rows are:  2,   8,   8,   18,   18,   32,   23.

The numbers 2, 8, 18, and 32 are twice the squares of 1, 2, 3, and 4.

The elements are numbered according to their place in the periodic table.

These numbers are the atomic numbers of the elements.