2.3 Chemical Properties and Reactions

Chemical Properties and Reactions

Structure of Matter

The Periodic Table

the periodic table

All the elements can be arranged in a periodic table in increasing order of atomic number and according to the number of electrons in their outer shell. When this is done, elements with similar properties are grouped together.

Each element occupies one block of the periodic table. There are many formats for the blocks of the periodic table. Here is a common format. In the example, the name of the element is calcium. Its chemical symbol is Ca. And its atomic number is 20, meaning that there are 20 protons in the nucleus of a calcium atom.

The horizontal rows of the periodic table are arranged in atomic number order with elements having one electron in the outer shell on the left (light metals), through elements having a full eight electrons in the outer shell on the right (noble gases). The vertical columns are called groups or families. Elements in a group show the same or similar properties.

Watch this video to find out more about the periodic table.