Antimony (Sb): Electron Configuration, Properties and Uses
Antimony (Sb): Electron Configuration, Properties and Uses
Electron configuration [Kr] 5s2 4d10 5p3 · group 15 · period 5 · Ar 121.76
Antimony data
- Atomic number
- 51
- Relative atomic mass
- 121.76
- Group
- 15
- Period
- 5
- Block
- p
- Category
- Metalloid
- Electron configuration
- [Kr] 5s2 4d10 5p3
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3
- Electrons per shell
- 2, 8, 18, 18, 5 (K L M N O)
- Valence electrons
- 5
- Electronegativity (Pauling)
- 2.05
- First ionisation energy
- 8.64 eV
- Atomic radius (van der Waals)
- 206 pm
- State at room temperature
- Solid
- Melting point
- 631 °C
- Boiling point
- 1587 °C
- Density
- 6.685 g/cm³
- Common oxidation states
- +5, +3, −3
- Discovered
- ancient times
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 18 · O 5
Orbital diagram (outer electrons)
About antimony
Antimony is a chemical element with the symbol Sb and atomic number 51. It is a metalloid in group 15, period 5, p-block. Antimony has been known and used since ancient times. The symbol Sb comes from the Latin stibium. Antimony is a solid at room temperature, melting at 631 °C and boiling at 1587 °C.
Antimony electron configuration
The electron configuration of antimony is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3, or in short [Kr] 5s2 4d10 5p3. Its electrons occupy 5 shells: K = 2, L = 8, M = 18, N = 18, O = 5. Antimony has 5 valence electrons in the O shell (5s2 5p3), which is why it sits in group 15.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s2(20) → 3d10(30) → 4p6(36) → 5s2(38) → 4d10(48) → 5p3(51)
Uses of antimony
The main uses of antimony include flame retardants (antimony trioxide), lead alloys for car batteries and semiconductors. For research and analysis you can browse antimony compounds in the AMI Scientific catalogue.
Safety
Some antimony compounds are toxic and should be handled per the SDS. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 15
Frequently asked questions
What is the electron configuration of antimony?
The electron configuration of antimony (Sb, atomic number 51) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3, or [Kr] 5s2 4d10 5p3 in short. By shell: 2, 8, 18, 18, 5.
How many valence electrons does antimony have?
Antimony has 5 valence electrons.
Which group and period is antimony in?
Antimony is in group 15, period 5, p-block.
What is the atomic mass of antimony?
The relative atomic mass of antimony is 121.76. Use it to calculate molar mass with the molar mass calculator.
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