Chemical element · Atomic number 95
Americium
Americium in the periodic table: atomic number 95, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Actinide
solid
[243.061380] u
A locally stored, license-verified sample photograph has not been curated yet.
Atomic classification
Shell occupancy
Americium in the Bohr shell model
This shows the electron distribution of the neutral atom in a simplified shell model.
- K · n=1
- 2 electrons
- L · n=2
- 8 electrons
- M · n=3
- 18 electrons
- N · n=4
- 32 electrons
- O · n=5
- 25 electrons
- P · n=6
- 8 electrons
- Q · n=7
- 2 electrons
- Electron configuration
- [Rn]7s2 5f7
- Electrons per shell
- 2 · 8 · 18 · 32 · 25 · 8 · 2
- Group
- not reported
- Period
- 7
- Block
- F
- Element category
- Actinide
Go from looking up chemistry to remembering it.
Turn your notes into source-backed study cards and review them at the right time.
Starter stays free · no payment details
Physical and chemical properties
- Atomic mass
- [243.061380] u
- Standard state
- solid
- Density
- 13.69 g/cm³
- Melting point
- 1,449 K
- Boiling point
- 2,284 K
- Electronegativity
- 1.3 (Pauling)
- First ionisation energy
- 5.993 eV
- Oxidation states
- +6, +5, +4, +3
- Discovery
- 1944
Safety and periodic classification
Safety
Safe handling cannot be inferred from Americium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.
Position and comparison
Americium is in period 7 and the F block. Its direct neighbours by atomic number are Plutonium and Curium. The recorded Pauling electronegativity is 1.3. Periodic trends are compared only through the separately sourced neighbouring values.
Sources and scope
PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.