How are elements arranged in the periodic table?

Elements in the periodic table are arranged in order of increasing atomic number, grouped by similar chemical properties.

The periodic table is a systematic way of organising the chemical elements, which are the building blocks of matter. It is arranged in rows and columns, with each box representing a different element. The elements are ordered by their atomic number, which is the number of protons in an atom's nucleus. This means that as you move from left to right across a row, or period, the atomic number increases.

The table is also divided into groups, or columns. Elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell. This outer shell, or valence shell, is crucial in determining how an element will react with others. For example, elements in Group 1, known as the alkali metals, are all highly reactive because they have one electron in their outer shell that they want to lose in order to achieve a stable electron configuration.

The periodic table is further divided into blocks. The s-block includes Groups 1 and 2, the p-block includes Groups 13 to 18, the d-block contains the transition metals, and the f-block contains the lanthanides and actinides. These blocks represent the subshell that is being filled with electrons as you move across the table.

The periodic table also separates metals, non-metals, and metalloids. Metals are on the left and centre of the table, non-metals are on the right, and metalloids, which have properties of both metals and non-metals, are found along the dividing line between metals and non-metals.

In summary, the arrangement of the periodic table provides a wealth of information about the elements and their properties, making it an essential tool for chemists.