Antimony (symbol Sb, atomic number 51) is a metalloid used in flame retardants and lead-acid battery alloys. It is classified as a metalloid and sits in group 15, period 5 of the periodic table.
Overview
Antimony is the chemical element with atomic number 51 and the symbol Sb. With a standard atomic weight of 121.76, it is a metalloid. In the periodic table it occupies group 15 and period 5, and under standard conditions it is normally a solid. Antimony is a metalloid used in flame retardants and lead-acid battery alloys.
Atomic structure
An atom of Antimony has 51 protons in its nucleus and, when neutral, 51 electrons arranged in the configuration [Kr] 4d10 5s2 5p3. Its standard atomic weight of 121.76 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Antimony has been known since antiquity. It follows Tin (Sn) and precedes Tellurium (Te) in order of atomic number.
| Atomic number | 51 |
|---|---|
| Symbol | Sb |
| Atomic mass | 121.76 |
| Category | Metalloid |
| Group | 15 |
| Period | 5 |
| Electron configuration | [Kr] 4d10 5s2 5p3 |
| Phase at STP | Solid |
| Discovered | Antiquity |