Element 3 · Alkali metal
Lithium (Li) — Element 3
Greek lithos — stone
Lithium (Li) is an alkali metal in Period 2, Group 1 of the periodic table with atomic number 3, standard atomic weight 6.94 u, and ground-state electron configuration [He] 2s¹. At standard temperature and pressure it is classified as a solid with 1 valence electron and common oxidation states +1.
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What are the atomic properties and physical constants of Lithium?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 3
- Standard atomic mass
- 6.94 u
- Chemical family
- Alkali metal
- Ground-state configuration
- [He] 2s¹
- Electrons per shell
- 2, 1
- Valence electrons
- 1
- Common ion charges / oxidation states
- +1
- Phase at STP
- Solid
- Pauling electronegativity
- 0.98 Pauling
- First ionization energy
- 520 kJ/mol
- Atomic radius
- 167 pm
- Melting point
- 181 °C
- Boiling point
- 1,342 °C
- Discovery year
- 1817
- Table coordinate
- Period 2, Group 1
- Radioactivity
- Has stable isotope(s)
How are electrons arranged across Lithium’s shells?
A neutral Lithium atom contains 3 electrons distributed across 2 occupied principal energy shells ([He] 2s¹). The table below compares Lithium’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Li | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 1 e⁻ | 8 e⁻ |
Frequently Asked Questions about Lithium (Li)
What is the atomic mass and atomic number of Lithium (Li)?
Lithium (Li) has atomic number Z = 3 (3 protons in its nucleus) and an IUPAC standard atomic weight of 6.94 u. It sits in Period 2, Group 1 and is classified as an alkali metal.
What is the ground-state electron configuration of Lithium?
The neutral ground-state electron configuration of Lithium (Z = 3) is [He] 2s¹. Across its 2 occupied principal shells (n = 1 to n = 2), the electrons per shell are 2, 1, with 1 valence electron participating in bonding.
What are the common ion charges and electronegativity of Lithium?
Lithium commonly forms +1 oxidation states or ion charges in compounds. Its Pauling electronegativity is 0.98 and its first ionization energy is 520 kJ/mol.
When was Lithium discovered and what is it used for?
Lithium was discovered in 1817 (Greek lithos — stone). Rechargeable batteries, mood-stabilizing medication
How does Lithium compare to neighboring elements?
Other alkali metal elements: