Element 95 · Americium (Am)

Americium Bohr model: diagram and electrons per shell

The americium Bohr model shows a americium atom (Am) as a small nucleus with its electrons circling it in 7 shells: 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q. This page has a rotating 3D americium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the americium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of americium (Am), a simplified picture of a single americium atom. Its nucleus holds 95 protons, and a neutral americium atom has 95 electrons, arranged around it in 7 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q).

Am K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 324s² 4p⁶ 4d¹⁰ 4f¹⁴ O · 255s² 5p⁶ 5d¹⁰ 5f⁷ P · 86s² 6p⁶ Q · 27s²

Americium Bohr model diagram

Bohr model diagram of americium: a nucleus of 95 protons with 95 electrons on 7 shells, 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q, each ring labelled with its shell letter. — The americium Bohr model drawn flat: each ring is a shell, labelled with its letter, and every dot is an electron (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q).

Americium electrons per shell

A neutral americium atom has 95 electrons, one for each of its 95 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q.

Electrons in each shell of the americium Bohr model
Shell	Shell number (n)	Electrons	Most it can hold (2n²)	Subshells
K	1	2	2	1s²
L	2	8	8	2s² 2p⁶
M	3	18	18	3s² 3p⁶ 3d¹⁰
N	4	32	32	4s² 4p⁶ 4d¹⁰ 4f¹⁴
O	5	25	50	5s² 5p⁶ 5d¹⁰ 5f⁷
P	6	8	72	6s² 6p⁶
Q	7	2	98	7s²

How the americium Bohr model builds up, shell by shell

Watch the americium Bohr model come together: the nucleus first, then each shell in turn, from the innermost outwards, with its electrons joining the ring. The legend names every shell and counts its electrons, so you can read off the arrangement (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q) as it forms.

Animation of the americium Bohr model being built: a nucleus of 95 protons appears first, then each shell grows in around it and takes its electrons, giving 95 electrons on 7 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q). — The americium Bohr model built up in six seconds: the nucleus first, then each shell with its electrons, ending with 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q. Protons are red, neutrons yellow and electrons blue.

How to draw the americium Bohr model

Find the atomic number. Americium has atomic number 95, so a neutral atom has 95 protons and 95 electrons.
Draw the nucleus. Put a circle in the centre and write Am in it. The 95 protons sit there with the neutrons.
Draw the shells. Sketch 7 shells as rings around the nucleus. A shell holds at most 2n² electrons: 2 in the first, 8 in the second, 18 in the third and 32 in the fourth.
Place the electrons. Fill from the inside out: 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 8 in shell P and 2 in shell Q.
Check the total. 2 + 8 + 18 + 32 + 25 + 8 + 2 = 95, the atomic number, so every electron is accounted for.

Atomic data for the americium Bohr model

The numbers behind the americium Bohr model, grouped by topic. Radii are in picometres (pm) and energies in kilojoules per mole (kJ/mol).

Identity

Symbol: Am
Atomic number: 95
Atomic mass: [243] u
Family: Actinides
Position: period 7 of the f-block
Block: f-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f⁷
Shorthand: [Rn] 5f⁷ 7s²
Electrons per shell: 2, 8, 18, 32, 25, 8, 2
Outer-shell electrons: 2 in shell Q

Ionisation energies

I₁: 578

Energy to remove each electron in turn (kJ/mol). A sharp jump means the next electron comes from an inner shell.

Atomic radii

Empirical (pm): 175
Covalent (pm): 166

Electronegativity and electron affinity

Electronegativity (Pauling): 1.13
Electron affinity (kJ/mol): 9.93

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of americium

Bulk properties of americium, how common it is, who discovered it and some of its compounds.

Physical properties

Phase at room conditions: Solid
Appearance: Silvery white
Melting point: 1175.85°C (1449 K)
Boiling point: 2606.85°C (2880 K)
Density: 12 g/cm³
Molar heat capacity (J/mol·K): 62.7
Heat of fusion (kJ/mol): 10
Heat of vaporisation (kJ/mol): 238.5

Discovery

Discovered by: Glenn T. Seaborg
Year: 1944

Common compounds

Americium Am
Americium AM-241 Am
Americium-243 Am
Americium chloride AmCl3
Americium citrate C6H5AmO7-3
Americium-242 Am
Americium-240 Am
Americium-244 Am

Compounds listed in the PubChem database.

Main isotopes of americium

Isotopes of americium share the same 95 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of americium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
239	–	11.9 h	EC, α
240	–	50.8 h	β⁺, α
241	–	432.6 y	α, SF
242	–	16.02 h	β⁻, EC
243	–	7.35 ky	α, SF
244	–	10.01 h	β⁻

α = alpha decay, β⁻ = beta-minus, β⁺ = beta-plus, EC = electron capture, SF = spontaneous fission, p / n = proton / neutron emission.

More about americium

Americium on the periodic table – properties, isotopes, uses and the full americium page.
Actinides – all actinide elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.