89 Ac
Actinide
Actinium
First actinide.
Properties of Actinium
- Atomic number (Z)
- 89
- Symbol
- Ac
- Atomic mass
- 227 g/mol
- Category
- Actinide
- Group
- 3
- Period
- 7
- Electron configuration
- [Rn] 6d¹ 7s²
- Electronegativity (Pauling)
- 1.1
- Atomic radius
- 195 pm
- First ionization energy
- 499 kJ/mol
- Melting point
- 1323 K (1049.8 °C)
- Boiling point
- 3471 K (3197.8 °C)
- Density
- 10.07 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1899
Frequently asked questions
What is Actinium?
Actinium (Ac) is an actinide, element number 89 on the periodic table. First actinide.
What is the atomic number and atomic mass of Actinium?
Actinium has atomic number 89 and an atomic mass of about 227 g/mol.
What is the electron configuration of Actinium?
The electron configuration of Actinium is [Rn] 6d¹ 7s².
Where is Actinium on the periodic table?
Actinium sits in group 3, period 7, and is classified as a actinide.