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The periodic table has un- dergone several updates and reorganizations since it was first developed in 1869, until the modern version of the table used today. The periodic table is arranged by increasing atomic

This carbon diagram shows the six protons orbiting the atom’s nucleus.

number, into rows and columns. Each element has a unique atomic number. It is the number of protons in the nucleus of the atom. For example, carbon has an atomic number of 6—there are six protons in the nucleus. All samples of an element have the same number of protons, but they may have a different number of neutrons in the nu- cleus. Atoms with the same number of protons but different number of neutrons are called isotopes. Each element on the periodic table is unique, having its own chemical and physical properties. But certain chemical properties can be interpreted based on which group or row an element resides in. The periodic table also gives information such as the number of protons and neutrons in the nucleus of one atom of an element, the number of electrons that surround the nucleus, the atomic mass, and the general size of the atom. It is also possible to

The Chemistry of Everyday Elements

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