Element 4 · Beryllium (Be)

Beryllium Bohr model: diagram and electrons per shell

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

Rotate the beryllium Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of beryllium (Be), a simplified picture of a single beryllium atom. Its nucleus holds 4 protons, and a neutral beryllium atom has 4 electrons, arranged around it in 2 shells (2 in shell K and 2 in shell L).

Be K · 21s² L · 22s²

Beryllium Bohr model diagram

Bohr model diagram of beryllium: a nucleus of 4 protons with 4 electrons on 2 shells, 2 in shell K and 2 in shell L, each ring labelled with its shell letter. — The beryllium Bohr model drawn flat: each ring is a shell, labelled with its letter, and every dot is an electron (2 in shell K and 2 in shell L).

Beryllium electrons per shell

A neutral beryllium atom has 4 electrons, one for each of its 4 protons. They fill the shells from the nucleus outwards: 2 in shell K and 2 in shell L.

Electrons in each shell of the beryllium Bohr model
Shell	Shell number (n)	Electrons	Most it can hold (2n²)	Subshells
K	1	2	2	1s²
L	2	2	8	2s²

How the beryllium Bohr model builds up, shell by shell

Watch the beryllium 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 and 2 in shell L) as it forms.

Animation of the beryllium Bohr model being built: a nucleus of 4 protons appears first, then each shell grows in around it and takes its electrons, giving 4 electrons on 2 shells (2 in shell K and 2 in shell L). — The beryllium Bohr model built up in six seconds: the nucleus first, then each shell with its electrons, ending with 2 in shell K and 2 in shell L. Protons are red, neutrons yellow and electrons blue.

How to draw the beryllium Bohr model

Find the atomic number. Beryllium has atomic number 4, so a neutral atom has 4 protons and 4 electrons.
Draw the nucleus. Put a circle in the centre and write Be in it. The 4 protons sit there with the neutrons.
Draw the shells. Sketch 2 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 and 2 in shell L.
Check the total. 2 + 2 = 4, the atomic number, so every electron is accounted for.

Atomic data for the beryllium Bohr model

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

Identity

Symbol: Be
Atomic number: 4
Atomic mass: 9.0122 u
Family: Alkaline Earth Metals
Position: group 2, period 2
Block: s-block

Electron configuration

Full: 1s² 2s²
Shorthand: [He] 2s²
Electrons per shell: 2, 2
Outer-shell electrons: 2 in shell L

Ionisation energies

I₁: 899.5
I₂: 1757.1
I₃: 14848.7
I₄: 21006.6

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): 112
Empirical (pm): 105
Covalent (pm): 102
Van der Waals (pm): 153

Electronegativity and electron affinity

Electronegativity (Pauling): 1.57
Electron affinity (kJ/mol): -48

Oxidation states

Charges the element commonly takes in compounds.

Physical properties, abundance and history of beryllium

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

Physical properties

Phase at room conditions: Solid
Appearance: White-gray metallic
Melting point: 1286.85°C (1560 K)
Boiling point: 2468.85°C (2742 K)
Density: 1.85 g/cm³
Thermal conductivity (W/m·K): 201
Specific heat (J/g·K): 1.825
Molar heat capacity (J/mol·K): 16.443
Heat of fusion (kJ/mol): 12.21
Heat of vaporisation (kJ/mol): 309

Abundance

Earth's crust (mg/kg): 2.8
Oceans (mg/L): 0

Discovery

Discovered by: Louis Nicolas Vauquelin
Year: 1798

Common compounds

Beryllium Be
Beryllium Oxide BeO
Beryllium Sulfate BeO4S
Beryllium nitrate BeN2O6
Beryllium Fluoride BeF2
Beryllium Chloride BeCl2
Beryllium Hydroxide BeH2O2
Beryllium sulfate tetrahydrate BeH8O8S

Compounds listed in the PubChem database.

Main isotopes of beryllium

Isotopes of beryllium share the same 4 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of beryllium: mass number, abundance, half-life and decay
Mass number	Natural abundance	Half-life	Decay
7	–	53.22 d	EC
9	100 %	stable	–
10	–	1.387 My	β⁻
11	–	13.76 s	β⁻, β⁻α, β⁻p, β⁻n
12	–	21.46 ms	β⁻, β⁻n
14	–	4.53 ms	β⁻, β⁻n, 2n, β⁻t, β⁻α

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

More about beryllium

Beryllium on the periodic table – properties, isotopes, uses and the full beryllium page.
Alkaline Earth Metals – all alkaline earth metal elements and their trends.
Bohr model of every element – the Bohr model of all 118 elements.