051Metalloid · Group 15 · Period 5
Antimony
Antimony (Sb) is element 51, a metalloid in the p-block — group 15, period 5. It is a solid at room temperature with 5 electron shells (2, 8, 18, 18, 5) and an atomic mass of 121.7601 u.
- Atomic mass
- 121.8 u
- Phase · STP
- solid
- Melting
- 904 K · 631 °C
- Boiling
- 1908 K · 1635 °C
- Electronegativity
- 2.05
- Density
- 6.697 g/cm³
Photograph — Unknown authorUnknown author, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/antimony.php
Identity
- Atomic number
- 51
- Standard atomic weight
- 121.8 u
- Category
- Metalloid
- Group
- 15 · Pnictogens
- Period
- 5
- Block
- p-block
- Oxidation states
- +5, +3, -3
Physical properties
- Melting point
- 904 K · 631 °C
- Boiling point
- 1908 K · 1635 °C
- Density
- 6.697 g/cm³
- Molar heat capacity
- 25.23 J/(mol·K)
- Atomic radius
- 206 pm
- Electron affinity
- 101.059 kJ/mol
Atomic structure
51protons
71neutrons
51electrons
5valence e⁻
- Noble-gas notation
- [Kr] 4d10 5s2 5p3
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3
- Electrons per shell
- 2, 8, 18, 18, 5
Periodic trends
Where Antimony ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
8341
1.6k2
2.4k3
4.3k4
5.4k5
10.4k6
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- Ancient
- Discovered by
- unknown, before 3000 BC
- Named by
- —
- Appearance
- silvery lustrous gray