Ac
Actinium Symbol (Ac)
Actinium is element 89 of the periodic table. Copy its symbol Ac and see its atomic weight, electron configuration and physical properties.
What does Ac mean?
Ac is the chemical symbol for actinium, element number 89 in the periodic table. Actinium is an actinide in the f-block, period 7. It is a solid at room temperature and was discovered in 1899.
Codes and properties
| Chemical symbol | Ac |
|---|---|
| Atomic number (Z) | 89 |
| Mass number (no standard atomic weight) | [227] |
| Group / period | f-block / 7 |
| Element category | actinide |
| Electron configuration | [Rn]7s² 6d¹ |
| State at 20 °C | Solid |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.1 |
| Melting point | 1324 K (1050.85 °C) |
| Boiling point | 3471 K (3197.85 °C) |
| Density | 10.07 g/cm³ |
| Discovered | 1899 |
How to type Ac
- Plain text: type
Ac— element symbols are ordinary Latin letters, with the first letter capitalised and the second lowercase. - Subscripts in formulas: use Unicode subscript digits (₀₁₂₃₄₅₆₇₈₉) for formulas such as H₂O — copy them from the chemistry keyboard.
- LaTeX: write
\mathrm{Ac}in math mode, or use the mhchem package:\ce{Ac}. - HTML:
Ac; for subscripts use<sub>, e.g.H<sub>2</sub>O.
Frequently asked questions
What is the chemical symbol for actinium?
The chemical symbol for actinium is Ac.
What is the atomic number of actinium?
Actinium has atomic number 89, meaning each atom has 89 protons.
What is the electron configuration of actinium?
The ground-state electron configuration of actinium is [Rn]7s² 6d¹.
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Reference: Actinium on PubChem (NIH)