Gallium

POST-TRANSITION METAL

Bohr Model: Electrons arranged in energy shells around the nucleus.

Gallium is a chemical element with symbol Ga and atomic number 31. Elemental gallium does not occur in free form in nature, but as the gallium(III) compounds that are in trace amounts in zinc ores and in bauxite. Gallium is a soft, silvery metal, and elemental gallium is a brittle solid at low temperatures, and melts at 29.76 °C (85.57 °F) (slightly above room temperature).

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Quick Facts

Atomic Number 31

Period 4

Group 13

Phase Solid

Appearance silver-white

About Post-Transition Metals

Transition metals are elements with partially filled d-orbitals. They are hard, have high melting points, and often form colored compounds.

History

Discovered By Lecoq de Boisbaudran

Named By Unknown

Physical Properties

Atomic Mass 69.7231

Density 5.91 g/L

Molar Heat 25.86 J/(mol·K)

Phase Transition (Melting & Boiling Points)

Gallium melts at 302.9146 K and boils at 2673 K.

Atomic Properties

Electron Config [Ar] 3d10 4s2 4p1

Electronegativity 1.81

Electron Affinity 41 kJ/mol

Ionization Energy 578.8 kJ/mol

Orbital Filling Diagram

This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule. Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down. Electrons fill lower energy levels first and occupy orbitals singly before pairing.

Photograph

Source: Wikipedia

External Resources

Wikipedia PubChem Royal Society of Chemistry Periodic Videos (YouTube)

Study Guide

Atomic Number

The number of protons in the nucleus, which defines the element.

Atomic Mass

The average mass of an atom, including protons and neutrons.

Electronegativity

A measure of how strongly an atom attracts electrons in a bond.

Ionization Energy

The energy required to remove an electron from an atom.

Electron Config

The arrangement of electrons in the atom's energy shells.