What is Gallium's atomic number?

Gallium has atomic number 31, meaning it has 31 protons in its nucleus. Its chemical symbol is Ga.

Why does Gallium melt in your hand?

Gallium's melting point is 29.76 °C (85.57 °F), just above room temperature. Normal body temperature (37 °C) is enough to liquefy it.

What is Gallium used for?

Gallium is essential in semiconductors — gallium arsenide (GaAs) powers high-speed electronics and solar cells, while gallium nitride (GaN) is used in LEDs and power transistors.

Gallium is considered low-toxicity in small amounts, but prolonged skin contact or ingestion is not recommended. It can alloy with and weaken aluminum and other metals on contact.

What is Gallium's electron configuration?

Gallium's full electron configuration is [Ar] 3d10 4s2 4p1. The single 4p electron is responsible for its +3 oxidation state and semiconductor behavior.

Who discovered Gallium?

Gallium was discovered in 1875 by French chemist Paul Emile Lecoq de Boisbaudran using spectroscopy. Mendeleev had predicted its existence years earlier as "eka-aluminum".

Gallium Element Properties

Name: Gallium Element Properties
Availability: InStock
Author: Nham Vu

Explore the complete physical and chemical properties of Gallium (Ga, element 31) — from its unusually low melting point to its semiconductor applications.

69.723

Gallium

Post-transition Metal · Period 4 · Group 13

Melting Point

29.76 °C

Boiling Point

2229 °C

Density

5.91 g/cm³

Atomic Mass

69.723 u

Electron Shell Configuration

[Ar] 3d¹⁰ 4s² 4p¹

Shells: 2, 8, 18, 3

Filter Properties

Property	Value
Element Name	Gallium
Symbol	Ga
Atomic Number	31
Atomic Mass	69.723 u
Category	Post-transition Metal
Group	13 (IIIA)
Period	4
Block	p-block
CAS Number	7440-55-3
Discovered	1875
Discovered By	Paul Emile Lecoq de Boisbaudran
Named After	Gallia (Latin for France)
Standard State	Solid at 25 °C
Appearance	Silvery-white, shiny metal

Property	Value
Electron Configuration	[Ar] 3d10 4s2 4p1
Electrons Per Shell	2, 8, 18, 3
Number of Protons	31
Number of Neutrons (Ga-69)	38
Number of Electrons	31
Valence Electrons	3
Oxidation States	+3 (primary), +1 (rare)
Electronegativity (Pauling)	1.81
Electron Affinity	28.9 kJ/mol
First Ionization Energy	578.8 kJ/mol
Second Ionization Energy	1979.3 kJ/mol
Third Ionization Energy	2963 kJ/mol
Atomic Radius (calc.)	136 pm
Covalent Radius	122 pm
Van der Waals Radius	187 pm
Stable Isotopes	Ga-69 (60.1%), Ga-71 (39.9%)

Property	Value
Melting Point	29.76 °C (85.57 °F / 302.91 K)
Boiling Point	2229 °C (4044 °F / 2502 K)
Density (solid, 29.6 °C)	5.91 g/cm³
Density (liquid, 29.8 °C)	6.095 g/cm³
Heat of Fusion	5.59 kJ/mol
Heat of Vaporization	254 kJ/mol
Specific Heat Capacity	0.371 J/(g·K)
Thermal Conductivity	40.6 W/(m·K)
Thermal Expansion	120 µm/(m·K)
Electrical Resistivity	270 nΩ·m (at 20 °C)
Young's Modulus	9.8 GPa
Brinell Hardness	56.8 MPa
Mohs Hardness	1.5
Crystal Structure	Orthorhombic (base-centered)
Magnetic Ordering	Diamagnetic
Speed of Sound	2740 m/s (liquid, 30 °C)

Property	Value
Reactivity	Low at room temperature; reacts with acids and bases
Reaction with Water	Very slow; forms Ga(OH)3 in hot water
Reaction with Air	Stable; thin oxide layer (Ga2O3) forms
Reaction with Acids	Dissolves in HCl, H2SO4 (dilute)
Reaction with Bases	Amphoteric; dissolves in NaOH (gallate ion)
Common Compounds	GaAs, GaN, Ga2O3, GaCl3, Ga2S3
Key Industrial Compound	Gallium arsenide (GaAs) — semiconductors
Key LED Compound	Gallium nitride (GaN) — blue/UV LEDs
Oxidation State Range	+1, +2, +3 (+3 most stable)
Amphoteric Nature	Yes — reacts with both acids and bases
Alloy Behavior	Alloys readily with most metals; embrittles aluminum
Toxicity	Low; non-essential trace element
Natural Occurrence	Trace mineral in bauxite, sphalerite, coal
Global Production	~320 tonnes/year (primarily from bauxite refining)

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Summary