Discovered By: Andre-Louis Debierne
Discovery year: 1899

The following table showing some properties of Actinium(Ac):

Table Example
Atomic number 89
Group n/a
Period 7
Block f
Electrons 89
Protons 89
Neutrons 138
Atomic weight (227)
Oxidation states +3
Ionic charge Ac^3+


Table Example
Electrons per shell K2 L8 M18 N32 O18 P9 Q2
Electon configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^14 5d^10 6p^6 7s^2 6d^1
Covalent radius 215 pm
Boiling point 3200°C
Melting point 1050°C
Phase Solid
Fusion heat 14 kJ.mol^-1
Vaporization heat 400 kJ.mol^-1
Specific heat 120 J.kg^-1.K^-1
Color Silver


Table Example
Density 10070 kg.m^-3
Molar volume 2.25*10^-5 m^3.mol^-1
Thermal conductivity 12 W.m^-1.K^-1
Electronegativity 1.1
Valence 3
First ionization energy 499 kJ.mol^-1
Radioactive Yes
Half life 6.8706*10^8 s
Lifetime 9.9121*10^8 s
Neutron cross section 880 barn
Decay mode Beta decay (β)