NEET Chemistry

Actinium: electronic configuration and properties

Actinium has atomic number 89 and electronic configuration [Rn] 6d1 7s2. Explore its periodic behaviour and open the interactive atom model.

Open Actinium in 3D

Key properties of Actinium

Symbol
Ac
Atomic number
89
Atomic mass
227
Family
actinoid
Electronic configuration
[Rn] 6d1 7s2
Shell distribution
2, 8, 18, 32, 18, 9, 2
Oxidation states
3
Standard state
solid

Periodic behaviour

Atomic radius: not experimentally determined. Electronegativity: 1.1. First ionisation energy: 499 kJ/mol. Use these values comparatively across a period or group rather than memorising them in isolation.

NEET exam focus

For NEET, prioritise the NCERT electronic configuration, periodic position, common oxidation states, and direct trend-based comparisons involving Actinium.

Related actinoid elements

Frequently asked questions

What is the electronic configuration of Actinium?

Actinium has electronic configuration [Rn] 6d1 7s2, with shell distribution 2, 8, 18, 32, 18, 9, 2.

What are the oxidation states of Actinium?

The listed oxidation states are 3.

How can I view the Actinium atom in 3D?

PracticeNEET's interactive periodic table provides a rotatable schematic atom with accurate electron populations by shell.