Element 96 · Curium (Cm)

Curium Bohr model: diagram and electrons per shell

The curium Bohr model shows a curium atom (Cm) 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, 9 in shell P and 2 in shell Q. This page has a rotating 3D curium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the curium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of curium (Cm), a simplified picture of a single curium atom. Its nucleus holds 96 protons, and a neutral curium atom has 96 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, 9 in shell P and 2 in shell Q).

Cm K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 324s² 4p⁶ 4d¹⁰ 4f¹⁴ O · 255s² 5p⁶ 5d¹⁰ 5f⁷ P · 96s² 6p⁶ 6d¹ Q · 27s²

Curium Bohr model diagram

Bohr model diagram of curium: a nucleus of 96 protons with 96 electrons on 7 shells, 2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 9 in shell P and 2 in shell Q, each ring labelled with its shell letter. — The curium 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, 9 in shell P and 2 in shell Q).

Curium electrons per shell

A neutral curium atom has 96 electrons, one for each of its 96 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, 9 in shell P and 2 in shell Q.

Electrons in each shell of the curium 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	9	72	6s² 6p⁶ 6d¹
Q	7	2	98	7s²

How the curium Bohr model builds up, shell by shell

Watch the curium 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, 9 in shell P and 2 in shell Q) as it forms.

Animation of the curium Bohr model being built: a nucleus of 96 protons appears first, then each shell grows in around it and takes its electrons, giving 96 electrons on 7 shells (2 in shell K, 8 in shell L, 18 in shell M, 32 in shell N, 25 in shell O, 9 in shell P and 2 in shell Q). — The curium 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, 9 in shell P and 2 in shell Q. Protons are red, neutrons yellow and electrons blue.

How to draw the curium Bohr model

Find the atomic number. Curium has atomic number 96, so a neutral atom has 96 protons and 96 electrons.
Draw the nucleus. Put a circle in the centre and write Cm in it. The 96 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, 9 in shell P and 2 in shell Q.
Check the total. 2 + 8 + 18 + 32 + 25 + 9 + 2 = 96, the atomic number, so every electron is accounted for.

Atomic data for the curium Bohr model

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

Identity

Symbol: Cm
Atomic number: 96
Atomic mass: [247] 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 6d¹
Shorthand: [Rn] 5f⁷ 6d¹ 7s²
Electrons per shell: 2, 8, 18, 32, 25, 9, 2
Outer-shell electrons: 2 in shell Q

Ionisation energies

I₁: 581

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): 176
Covalent (pm): 166

Electronegativity and electron affinity

Electronegativity (Pauling): 1.28
Electron affinity (kJ/mol): 27.17

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of curium

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

Physical properties

Phase at room conditions: Solid
Appearance: Silvery metallic, glows purple in the dark
Melting point: 1339.85°C (1613 K)
Boiling point: 3109.85°C (3383 K)
Density: 13.51 g/cm³

Discovery

Discovered by: Glenn T. Seaborg
Year: 1944

Common compounds

Curium Cm
Curium-244 Cm
Curium-243 Cm
Curium-242 Cm
Curium-241 Cm
Curium, isotope of mass 245 Cm
Curium-249 Cm
Curium-246 Cm

Compounds listed in the PubChem database.

Main isotopes of curium

Isotopes of curium share the same 96 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of curium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
243	–	29.1 y	α, EC, SF
244	–	18.11 y	α, SF
245	–	8.25 ky	α, SF
246	–	4.706 ky	α, SF
247	–	15.6 My	α
248	–	348 ky	α, SF, 2β⁻

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

More about curium

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