24Cr51.996
Transition Metald-block
Chromium
Element 24 on the periodic table, symbol Cr, group 6, period 4.
Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.
Appearance: silvery metallic
Properties
- Atomic Number
- 24
- Atomic Mass
- 51.9962 u
- Group
- 6
- Period
- 4
- Block
- d-block
- Category
- Transition Metal
- State at 25 °C
- Solid
- Melting Point
- 2,180 K · 1,906.9 °C
- Boiling Point
- 2,944 K · 2,670.9 °C
- Density
- 7.19 g/cm³
- Atomic Radius
- 140 pm
- Electronegativity
- 1.66
- Oxidation States
- +2, +3, +6
- Abundance in Crust
- 102 mg/kg
- Discovered
- 1797
- Discovered By
- Louis Nicolas Vauquelin
Electron Configuration
[Ar] 3d5 4s1
1s2 2s2 2p6 3s2 3p6 4s1 3d5
Ionisation Energies (kJ/mol)
- 1. 652.9
- 2. 1,590.6
- 3. 2,987
- 4. 4,743
- 5. 6,702
- 6. 8,744.9
- 7. 15,455
- 8. 17,820
Elements near Chromium
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.