Element 48 · Cadmium (Cd)

Cadmium Bohr model: diagram and electrons per shell

The cadmium Bohr model shows a cadmium atom (Cd) as a small nucleus with its electrons circling it in 5 shells: 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 2 in shell O. This page has a rotating 3D cadmium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the cadmium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of cadmium (Cd), a simplified picture of a single cadmium atom. Its nucleus holds 48 protons, and a neutral cadmium atom has 48 electrons, arranged around it in 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 2 in shell O).

Cd K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 184s² 4p⁶ 4d¹⁰ O · 25s²

Cadmium Bohr model diagram

Bohr model diagram of cadmium: a nucleus of 48 protons with 48 electrons on 5 shells, 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 2 in shell O, each ring labelled with its shell letter. — The cadmium 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, 18 in shell N and 2 in shell O).

Cadmium electrons per shell

A neutral cadmium atom has 48 electrons, one for each of its 48 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 2 in shell O.

Electrons in each shell of the cadmium 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	18	32	4s² 4p⁶ 4d¹⁰
O	5	2	50	5s²

How the cadmium Bohr model builds up, shell by shell

Watch the cadmium 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, 18 in shell N and 2 in shell O) as it forms.

Animation of the cadmium Bohr model being built: a nucleus of 48 protons appears first, then each shell grows in around it and takes its electrons, giving 48 electrons on 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 18 in shell N and 2 in shell O). — The cadmium 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, 18 in shell N and 2 in shell O. Protons are red, neutrons yellow and electrons blue.

How to draw the cadmium Bohr model

Find the atomic number. Cadmium has atomic number 48, so a neutral atom has 48 protons and 48 electrons.
Draw the nucleus. Put a circle in the centre and write Cd in it. The 48 protons sit there with the neutrons.
Draw the shells. Sketch 5 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, 18 in shell N and 2 in shell O.
Check the total. 2 + 8 + 18 + 18 + 2 = 48, the atomic number, so every electron is accounted for.

Atomic data for the cadmium Bohr model

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

Identity

Symbol: Cd
Atomic number: 48
Atomic mass: 112.4144 u
Family: Transition Metals
Position: group 12, period 5
Block: d-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰
Shorthand: [Kr] 4d¹⁰ 5s²
Electrons per shell: 2, 8, 18, 18, 2
Outer-shell electrons: 2 in shell O

Ionisation energies

I₁: 867.8
I₂: 1631.4
I₃: 3616

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

Atomic radii

Calculated (pm): 161
Empirical (pm): 155
Covalent (pm): 136
Van der Waals (pm): 158

Electronegativity and electron affinity

Electronegativity (Pauling): 1.69
Electron affinity (kJ/mol): -68

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of cadmium

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

Physical properties

Phase at room conditions: Solid
Appearance: Silvery bluish-gray metallic
Melting point: 321.07°C (594.22 K)
Boiling point: 766.85°C (1040 K)
Density: 8.65 g/cm³
Thermal conductivity (W/m·K): 96.9
Specific heat (J/g·K): 0.232
Molar heat capacity (J/mol·K): 26.02
Heat of fusion (kJ/mol): 6.11
Heat of vaporisation (kJ/mol): 59.1

Abundance

Earth's crust (mg/kg): 0.15
Oceans (mg/L): 0

Discovery

Discovered by: Karl Samuel Leberecht Hermann
Year: 1817
Named by: Isotopes of cadmium

Common compounds

Cadmium Cd
Cadmium Chloride CdCl2
Cadmium Sulfide CdS
Cadmium cation Cd+2
Cadmium Sulfate CdO4S
Cadmium carbonate (CdCO3) CCdO3
Cadmium acetate C4H6CdO4
Cadmium Oxide CdO

Compounds listed in the PubChem database.

Main isotopes of cadmium

Isotopes of cadmium share the same 48 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of cadmium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
110	12.47 %	stable	–
111	12.795 %	stable	–
112	24.109 %	stable	–
113	12.227 %	8.04 Py	β⁻
114	28.754 %	stable	2β⁻
116	7.512 %	26.9 Ey	2β⁻

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

More about cadmium

Cadmium on the periodic table – properties, isotopes, uses and the full cadmium page.
Transition Metals – all transition metal elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.