Antimony (Sb) – element 51
Antimony is a chemical element with the symbol Sb and atomic number 51. It is a metalloid in group 15 (pnictogens), period 5 of the periodic table (p-block), and is a solid at room temperature.
Antimony (Sb) has atomic number 51, atomic mass 121.76 u and electron configuration [Kr] 4d10 5s2 5p3.
Antimony facts
| Symbol | Sb |
|---|---|
| Atomic number | 51 |
| Atomic mass | 121.76 u (g/mol) |
| Category | metalloid |
| Group | group 15 (pnictogens) |
| Period | 5 |
| Block | p-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3 |
| Noble-gas notation | [Kr] 4d10 5s2 5p3 |
| Electrons per shell | 2, 8, 18, 18, 5 |
| Valence electrons | 5 |
Bohr model and shells
Antimony has 51 electrons in 5 shells: 2, 8, 18, 18, 5. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 903.78 K (630.6 °C) |
|---|---|
| Boiling point | 1908 K (1634.8 °C) |
| Density | 6.697 g/cm³ |
| Electronegativity (Pauling) | 2.05 |
| Electron affinity | 101.059 kJ/mol |
| Ionization energies | 834, 1594.9, 2440 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 25.23 J/(mol·K) |
| Discovered by | unknown, before 3000 BC |
Use the atomic mass in the molar mass calculator for any formula containing Sb.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of antimony?
The atomic mass of antimony is 121.76 u, so one mole of antimony atoms weighs 121.76 g.
What is the electron configuration of antimony?
Antimony has 51 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p³, or [Kr] 4d¹⁰ 5s² 5p³ in noble-gas notation. Electrons per shell: 2, 8, 18, 18, 5.
How many valence electrons does antimony have?
Antimony has 5 valence electrons (group 15).
Is antimony a metal?
Antimony is a metalloid: it has properties between metals and nonmetals.
Where is antimony on the periodic table?
Antimony is in group 15 (pnictogens), period 5, in the p-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.