Element 21
Scandium (Sc)
Scandium (Sc) is element 21 of the periodic table, a transition metal in period 4, group 3 (d-block) with an atomic mass of 44.956 and is a solid at standard conditions.
At a glance
- Atomic number
- 21
- Symbol
- Sc
- Atomic mass
- 44.956 u
- Category
- Transition metals
- Period
- 4
- Group
- 3
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d1 4s2
- Shorthand configuration
- [Ar] 3d1 4s2
- Electrons per shell
- 2, 8, 9, 2
- Oxidation states
- +1, +2, +3
Physical properties
- Melting point
- 1,814 K (1,540.85 °C)
- Boiling point
- 3,109 K (2,835.85 °C)
- Density
- 2.989 g/cm³
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.36
- Atomic radius
- 184 pm
- Covalent radius
- 170 pm
- Van der Waals radius
- 211 pm
- First ionization energy
- 633 kJ/mol
- Electron affinity
- 18 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Sc-45 | 44.95591 | 100% | Stable |
Common uses
- Aerospace alloys
- Sports equipment
- Lighting
- Lasers
Discovery
- Year
- 1879
- Discovered by
- Lars Fredrik Nilson
- Country
- Sweden
Frequently asked questions
- Is scandium a metal?
- Yes. Scandium is a metal, classified as a transition metal on the periodic table.
- How many protons does scandium have?
- Scandium has 21 protons. Its atomic number is 21, which is also the number of electrons in a neutral atom of scandium.
- What group and period is scandium in?
- Scandium is in group 3 and period 4 of the periodic table, in the d-block.
- What is the atomic mass of scandium?
- The atomic mass of scandium is 44.956 u (unified atomic mass units).
Keep exploring
Scandium's row is on the printable element property sheet, and its tile is on the periodic table wall chart - the same numbers as above, laid out for A4 or A3 paper.