Symbol

Ga

Atomic Number

31

Atomic Mass

69.72

Family

Group 13 (Iiia) Aluminum Pronunciation

GA-le-um

Overview

In the late 1860s Russian chemist Dmitri Mendeleev (1834- 1907) made one of the greatest discoveries in modern chemistry: the periodic law. The periodic law describes how chemical elements are related to each other. These elements are in the periodic table. This is a chart that lists all of the chemical elements and sorts them into groups based on similarities. Elements in vertical columns are similar to each other in many ways.

When Mendeleev first proposed the periodic law, he made a troubling discovery. There were a few empty spots in his table. For example, the box set aside for element number 31 was empty. No element had been found that belonged in that box.

Part of Mendeleev's genius was what he did next. He said that an "element number 31" did exist. Scientists simply had not found...