Element 40 · Zirconium (Zr)

Zirconium Bohr model: diagram and electrons per shell

The zirconium Bohr model shows a zirconium atom (Zr) as a small nucleus with its electrons circling it in 5 shells: 2 in shell K, 8 in shell L, 18 in shell M, 10 in shell N and 2 in shell O. This page has a rotating 3D zirconium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the zirconium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of zirconium (Zr), a simplified picture of a single zirconium atom. Its nucleus holds 40 protons, and a neutral zirconium atom has 40 electrons, arranged around it in 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 10 in shell N and 2 in shell O).

Zr K · 21s² L · 82s² 2p⁶ M · 183s² 3p⁶ 3d¹⁰ N · 104s² 4p⁶ 4d² O · 25s²

Zirconium Bohr model diagram

Bohr model diagram of zirconium: a nucleus of 40 protons with 40 electrons on 5 shells, 2 in shell K, 8 in shell L, 18 in shell M, 10 in shell N and 2 in shell O, each ring labelled with its shell letter. — The zirconium 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, 10 in shell N and 2 in shell O).

Zirconium electrons per shell

A neutral zirconium atom has 40 electrons, one for each of its 40 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M, 10 in shell N and 2 in shell O.

Electrons in each shell of the zirconium 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	10	32	4s² 4p⁶ 4d²
O	5	2	50	5s²

How the zirconium Bohr model builds up, shell by shell

Watch the zirconium 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, 10 in shell N and 2 in shell O) as it forms.

Animation of the zirconium Bohr model being built: a nucleus of 40 protons appears first, then each shell grows in around it and takes its electrons, giving 40 electrons on 5 shells (2 in shell K, 8 in shell L, 18 in shell M, 10 in shell N and 2 in shell O). — The zirconium 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, 10 in shell N and 2 in shell O. Protons are red, neutrons yellow and electrons blue.

How to draw the zirconium Bohr model

Find the atomic number. Zirconium has atomic number 40, so a neutral atom has 40 protons and 40 electrons.
Draw the nucleus. Put a circle in the centre and write Zr in it. The 40 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, 10 in shell N and 2 in shell O.
Check the total. 2 + 8 + 18 + 10 + 2 = 40, the atomic number, so every electron is accounted for.

Atomic data for the zirconium Bohr model

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

Identity

Symbol: Zr
Atomic number: 40
Atomic mass: 91.2242 u
Family: Transition Metals
Position: group 4, period 5
Block: d-block

Electron configuration

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d²
Shorthand: [Kr] 4d² 5s²
Electrons per shell: 2, 8, 18, 10, 2
Outer-shell electrons: 2 in shell O

Ionisation energies

I₁: 640.1
I₂: 1270
I₃: 2218
I₄: 3313
I₅: 7752
I₆: 9500

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): 206
Empirical (pm): 155
Covalent (pm): 154

Electronegativity and electron affinity

Electronegativity (Pauling): 1.33
Electron affinity (kJ/mol): 41.806

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of zirconium

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

Physical properties

Phase at room conditions: Solid
Appearance: Silvery white
Melting point: 1854.85°C (2128 K)
Boiling point: 4376.85°C (4650 K)
Density: 6.52 g/cm³
Thermal conductivity (W/m·K): 22.7
Specific heat (J/g·K): 0.278
Molar heat capacity (J/mol·K): 25.36
Heat of fusion (kJ/mol): 19.2
Heat of vaporisation (kJ/mol): 567

Abundance

Earth's crust (mg/kg): 165
Oceans (mg/L): 0

Discovery

Discovered by: Martin Heinrich Klaproth
Year: 1789

Common compounds

Zirconium Zr
Zirconium sulfate O8S2Zr
Zirconium chloride Cl4Zr
Sodium Zirconium Cyclosilicate Na2O9Si3Zr
Silicic acid, zirconium(4+) salt O4SiZr
Lead zirconate titanate O5PbTiZr
Zirconium picramate C24H16N12O20Zr
Barium zirconium oxide BaO3Zr

Compounds listed in the PubChem database.

Main isotopes of zirconium

Isotopes of zirconium share the same 40 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of zirconium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
90	51.45 %	stable	–
91	11.22 %	stable	–
92	17.15 %	stable	–
93	–	1.61 My	β⁻
94	17.38 %	stable	2β⁻
96	2.8 %	23.4 Ey	2β⁻

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

More about zirconium

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