Americium
Element 95 on the periodic table, symbol Am, group 3, period 7.
Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.
Appearance: silvery white
Properties
- Atomic Number
- 95
- Atomic Mass
- 243.0000 u
- Group
- 3
- Period
- 7
- Block
- f-block
- Category
- Actinide
- State at 25 °C
- Solid
- Melting Point
- 1,449 K · 1,175.9 °C
- Boiling Point
- 2,880 K · 2,606.9 °C
- Density
- 12 g/cm³
- Atomic Radius
- 175 pm
- Electronegativity
- 1.13
- Oxidation States
- +3
- Abundance in Crust
- Vanishingly rare
- Discovered
- 1944
- Discovered By
- Glenn T. Seaborg
Electron Configuration
[Rn] 5f7 7s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f7
Ionisation Energies (kJ/mol)
- 1. 578
Elements near Americium
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.