Beryllium (symbol Be, atomic number 4) is a light, stiff metal prized for X-ray windows and aerospace alloys, but highly toxic. It is classified as a alkaline earth metal and sits in group 2, period 2 of the periodic table.
Overview
Beryllium is the chemical element with atomic number 4 and the symbol Be. With a standard atomic weight of 9.0122, it is a alkaline earth metal. In the periodic table it occupies group 2 and period 2, and under standard conditions it is normally a solid. Beryllium is a light, stiff metal prized for X-ray windows and aerospace alloys, but highly toxic.
Atomic structure
An atom of Beryllium has 4 protons in its nucleus and, when neutral, 4 electrons arranged in the configuration [He] 2s2. Its standard atomic weight of 9.0122 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Beryllium was discovered in 1798 by Louis Nicolas Vauquelin. It follows Lithium (Li) and precedes Boron (B) in order of atomic number.
| Atomic number | 4 |
|---|---|
| Symbol | Be |
| Atomic mass | 9.0122 |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 2 |
| Electron configuration | [He] 2s2 |
| Phase at STP | Solid |
| Discovered | 1798 (Louis Nicolas Vauquelin) |