Antimony (Sb)
Element 51 · metalloid · group 15, period 5
Antimony is element 51, a metalloid in group 15 and period 5. Its electron configuration is [Kr] 4d10 5s2 5p3. That leaves 5 valence electrons in the outer shell, with the shells filling 2, 8, 18, 18, 5. It is 3 electrons short of a full octet, so it gains them and carries a charge of +3, +5.
- 51 protons
- 5 valence e−
- +3, +5
- p-block
Properties
| Atomic number | 51 |
|---|---|
| Symbol | Sb |
| Standard atomic weight | 121.76 u |
| Group | 15 |
| Period | 5 |
| Block | p-block |
| Category | metalloid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3 |
| Noble-gas notation | [Kr] 4d10 5s2 5p3 |
| Electrons per shell | 2, 8, 18, 18, 5 |
| Valence electrons | 5 |
| Common ionic charge | +3, +5 |
| Electronegativity (Pauling) | 2.05 |
| Protons / electrons | 51 / 51 |
Electron configuration of antimony
Orbitals fill from the lowest energy upward. Writing that out for antimony gives 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3, which is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3 in plain text.
Everything up to Kr is the same as in that noble gas, so it is usually abbreviated to [Kr] 4d10 5s2 5p3. The part outside the bracket is what does the chemistry.
| Subshell | Electrons | Capacity |
|---|---|---|
| 1s | 2 | 2 |
| 2s | 2 | 2 |
| 2p | 6 | 6 |
| 3s | 2 | 2 |
| 3p | 6 | 6 |
| 3d | 10 | 10 |
| 4s | 2 | 2 |
| 4p | 6 | 6 |
| 4d | 10 | 10 |
| 5s | 2 | 2 |
| 5p | 3 | 6 |
Antimony ion charge
Antimony commonly forms ions with a charge of +3, +5.
It has 5 valence electrons, so it is 3 short of a full octet and 5 above an empty outer shell. An atom takes whichever route is shorter, which is why the charge comes out as it does.
Common questions
How many valence electrons does antimony have?
Antimony has 5 valence electrons. For a main-group element the count is the group number minus 10, and antimony is in group 15.
What is the electron configuration of antimony?
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3, or [Kr] 4d10 5s2 5p3 written from the previous noble gas. Orbitals fill lowest energy first.
What is the charge of antimony?
Antimony commonly forms ions with a charge of +3, +5. With 5 valence electrons it is 3 short of an octet and 5 above an empty shell, so it takes whichever route is shorter.
How many protons, electrons and neutrons does antimony have?
A neutral antimony atom has 51 protons and 51 electrons. Its standard atomic weight is 121.76, so the most common isotope has about 71 neutrons.
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