Antimony (Sb): electron configuration, atomic mass and facts
Antimony (Sb) is element 51 of the periodic table, a metalloid in period 5, group 15. Its electron configuration is [Kr] 4d10 5s2 5p3, with electrons arranged in shells 2, 8, 18, 18, 5, and its standard atomic weight is 121.76 u.
▶ Watch Antimony’s electrons orbit in the interactive periodic tableAntimony at a glance
| Symbol | Sb |
|---|---|
| Atomic number | 51 |
| Atomic mass | 121.76 u |
| Category | Metalloid |
| Group | 15 |
| Period | 5 |
| Block | p-block |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3 |
| Noble-gas shorthand | [Kr] 4d10 5s2 5p3 |
| Electrons per shell | 2, 8, 18, 18, 5 |
| Outer-shell electrons | 5 |
| Electronegativity (Pauling) | 2.05 |
| State at 20 °C | solid |
Where is Antimony on the periodic table?
Antimony is in period 5, group 15, in the p-block. The period number matches its 5 electron shells, and the block names the subshell its last electrons fill. In the same group, Arsenic sits directly above it and Bismuth sits directly below it. Elements in one group have the same number of outer-shell electrons (5 here), which is why they react in similar ways.
How to work out the electron configuration of Antimony
Put 51 electrons into subshells in order of rising energy, filling each before starting the next: 1s² (2), 2s² (4), 2p⁶ (10), 3s² (12), 3p⁶ (18), 4s² (20), 3d¹⁰ (30), 4p⁶ (36), 5s² (38), 4d¹⁰ (48), 5p³ (51). In shorthand, [Kr] stands for the 36 electrons of krypton, giving [Kr] 4d¹⁰ 5s² 5p³.
How electronegative is Antimony?
Antimony has a Pauling electronegativity of 2.05, ranking 28 of the 100 elements with a known value (fluorine is highest at 3.98). That is in the middle of the range.
Frequently asked questions
What is the electron configuration of Antimony?
The electron configuration of Antimony (Sb) is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3. In noble-gas shorthand it is written [Kr] 4d10 5s2 5p3.
How many electrons does Antimony have in each shell?
Antimony has 51 electrons arranged in shells as 2, 8, 18, 18, 5. It has 5 electrons in its outer shell.
What is the atomic mass of Antimony?
The standard atomic weight of Antimony is 121.76 u, so one mole of Antimony atoms has a mass of about 121.76 g.
Is Antimony a metal?
Antimony is a metalloid: its properties sit between those of metals and nonmetals.
Explore nearby elements
More metalloids: Boron, Silicon, Germanium, Arsenic, Tellurium. See all elements on the periodic table.