Information valid for Ac-227 unless otherwise noted

Actinium

Basic Information

Symbol: Ac
Atomic Number: 89
Mass: (227.0)
Melting Point: 1050.0 C
Boiling Point: 3200.0 C
Number of Protons/Electrons: 89
Number of Neutrons: 138
Classification: Rare Earth
Crystal Structure: Cubic
Density @ 293 K: 10.07 g/cm³
Color: Silvery

Atomic Structure

Number of Energy Levels: 7 First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 32 Fifth Energy Level: 18 Sixth Energy Level: 9 Seventh Energy Level: 2

Isotopes

Facts

Date of Discovery: 1899
Discoverer: Andre Debierne
Name Origin: From the Greek word aktinos (ray)
Uses: No uses known
Obtained From: extremely rare