Element 21 · Scandium (Sc)
Scandium Bohr model: diagram and electrons per shell
The scandium Bohr model shows a scandium atom (Sc) as a small nucleus with its electrons circling it in 4 shells: 2 in shell K, 8 in shell L, 9 in shell M and 2 in shell N. This page has a rotating 3D scandium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.
Rotate the scandium Bohr model in 3D
Drag to orbit, scroll to zoom.
This is a Bohr model of scandium (Sc), a simplified picture of a single scandium atom. Its nucleus holds 21 protons, and a neutral scandium atom has 21 electrons, arranged around it in 4 shells (2 in shell K, 8 in shell L, 9 in shell M and 2 in shell N).
Scandium Bohr model diagram
Scandium electrons per shell
A neutral scandium atom has 21 electrons, one for each of its 21 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 9 in shell M and 2 in shell N.
| Shell | Shell number (n) | Electrons | Most it can hold (2n²) | Subshells |
|---|---|---|---|---|
| K | 1 | 2 | 2 | 1s2 |
| L | 2 | 8 | 8 | 2s2 2p6 |
| M | 3 | 9 | 18 | 3s2 3p6 3d1 |
| N | 4 | 2 | 32 | 4s2 |
How the scandium Bohr model builds up, shell by shell
Watch the scandium 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, 9 in shell M and 2 in shell N) as it forms.
How to draw the scandium Bohr model
- Find the atomic number. Scandium has atomic number 21, so a neutral atom has 21 protons and 21 electrons.
- Draw the nucleus. Put a circle in the centre and write Sc in it. The 21 protons sit there with the neutrons.
- Draw the shells. Sketch 4 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, 9 in shell M and 2 in shell N.
- Check the total. 2 + 8 + 9 + 2 = 21, the atomic number, so every electron is accounted for.
Atomic data for the scandium Bohr model
The numbers behind the scandium Bohr model, grouped by topic. Radii are in picometres (pm) and energies in kilojoules per mole (kJ/mol).
Identity
- Symbol
- Sc
- Atomic number
- 21
- Atomic mass
- 44.9559 u
- Family
- Transition Metals
- Position
- group 3, period 4
- Block
- d-block
Electron configuration
- Full
- 1s2 2s2 2p6 3s2 3p6 4s2 3d1
- Shorthand
- [Ar] 3d1 4s2
- Electrons per shell
- 2, 8, 9, 2
- Outer-shell electrons
- 2 in shell N
Ionisation energies
- I₁
- 633.1
- I₂
- 1235
- I₃
- 2388.6
- I₄
- 7090.6
- I₅
- 8843
- I₆
- 10679
- I₇
- 13310
- I₈
- 15250
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)
- 184
- Empirical (pm)
- 160
- Covalent (pm)
- 148
- Van der Waals (pm)
- 211
Electronegativity and electron affinity
- Electronegativity (Pauling)
- 1.36
- Electron affinity (kJ/mol)
- 18
Oxidation states
+3
Charges the element commonly takes in compounds.
Physical properties, abundance and history of scandium
Bulk properties of scandium, how common it is, who discovered it and some of its compounds.
Physical properties
- Phase at room conditions
- Solid
- Appearance
- Silvery white
- Melting point
- 1540.85°C (1814 K)
- Boiling point
- 2835.85°C (3109 K)
- Density
- 2.985 g/cm³
- Thermal conductivity (W/m·K)
- 15.8
- Specific heat (J/g·K)
- 0.568
- Molar heat capacity (J/mol·K)
- 25.52
- Heat of fusion (kJ/mol)
- 15.8
- Heat of vaporisation (kJ/mol)
- 332.7
Abundance
- Earth's crust (mg/kg)
- 22
- Oceans (mg/L)
- 0
Discovery
- Discovered by
- Lars Fredrik Nilson
- Year
- 1879
Common compounds
- Scandium Sc
- Scandium chloride Cl3Sc
- Scandium nitrate N3O9Sc
- Scandium phosphide (ScP) PSc
- Scandium nitride (ScN) NSc
- Scandium iodide I3Sc
- Scandium fluoride F3Sc
- Scandium hydroxide (Sc(OH)3) H3O3Sc
Compounds listed in the PubChem database.
Main isotopes of scandium
Isotopes of scandium share the same 21 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.
| Mass number | Natural abundance | Half-life | Decay |
|---|---|---|---|
| 43 | – | 3.891 h | β⁺ |
| 44 | – | 4.042 h | β⁺ |
| 45 | 100 % | stable | – |
| 46 | – | 83.757 d | β⁻ |
| 47 | – | 3.349 d | β⁻ |
| 48 | – | 43.67 h | β⁻ |
α = alpha decay, β⁻ = beta-minus, β⁺ = beta-plus, EC = electron capture, SF = spontaneous fission, p / n = proton / neutron emission.
More about scandium
- Scandium on the periodic table – properties, isotopes, uses and the full scandium page.
- Transition Metals – all transition metal elements and their trends.
- Bohr model of every element – the Bohr model of all 118 elements.