What is Gallium Definition Properties Reactions and Uses
Gallium is essential in chemistry and helps students understand various practical and theoretical applications related to this topic.
What is Gallium in Chemistry?
A gallium refers to a soft, silvery metal with atomic number 31, belonging to group 13 of the periodic table. This concept appears in chapters related to elements, periodic trends, and semiconductor materials, making it a foundational part of your chemistry syllabus.
Gallium is best known for its low melting point—just above room temperature—and its wide use in electronics like LEDs and semiconductors.
Molecular Formula and Composition
The molecular formula of gallium as an element is simply "Ga." It consists of only gallium atoms and is categorized under the class of post-transition metals from group 13.
In its compounds, such as gallium arsenide (GaAs) and gallium nitride (GaN), it combines with other elements to offer valuable semiconductor behavior. Gallium has an atomic mass of 69.72 g/mol, and it often features in chemistry classes when discussing the physical and atomic properties of elements.
Preparation and Synthesis Methods
Gallium is not found free in nature. Instead, it is extracted mainly as a by-product during the refining of aluminum (from bauxite) and zinc ores. Industrially, gallium is separated by electrolysis or chemical displacement from the solutions left after these ores are processed.
Laboratory preparation involves passing an electric current through gallium compounds or smelting gallium-containing minerals. This practical knowledge ties into the extraction of metals unit in your syllabus.
Physical Properties of Gallium
Gallium has several unusual physical properties that make it a topic of curiosity:
- Melting point: about 29.8°C (can melt in your hand)
- Boiling point: 2204°C (very high compared to its melting point)
- Density: 5.91 g/cm³
- Appearance: Silvery, shiny, and soft—can be cut with a knife
- State: Solid at room temperature, but melts slightly above it
- Solubility: Stable in water and air, not highly reactive
- Odor: Odorless
Chemical Properties and Reactions
Gallium is not as reactive as alkali metals but can form several useful compounds:
- Forms gallium(III) oxide when heated with oxygen
- Reacts with both acids and alkalis, showing amphoteric behavior
- Can diffuse into other metals like aluminum and gold, making them brittle
- Forms important semiconducting compounds such as gallium arsenide (GaAs) and gallium nitride (GaN)
Frequent Related Errors
- Confusing gallium with other liquid metals like mercury (Ga is less toxic and less reactive)
- Assuming gallium is dangerous to touch—it's not toxic, but can slightly stain skin
- Mixing up the group number or period in the periodic table—gallium is in group 13
- Forgetting its solid-liquid transition near room temperature for exam questions
Uses of Gallium in Real Life
Gallium is widely used in several high-tech and everyday applications:
- Manufacture of semiconductors, especially gallium arsenide (GaAs) chips for electronics
- Production of LEDs and laser diodes
- Special glass mirrors and thermometers as a safe alternative to mercury
- Medical imaging and radiopharmaceuticals (e.g., gallium-67 scans)
- Alloys—gallium forms low-melting alloys used in temperature-sensitive devices
Step-by-Step Reaction Example
- Prepare a strip of aluminum and place a drop of liquid gallium on its surface.
Gallium diffuses into the grain boundaries of aluminum, weakening it. - Observe the aluminum structure after a few hours.
The aluminum becomes brittle and can be easily broken apart—the basis for a famous chemistry demonstration.
Lab or Experimental Tips
Remember gallium by the rule: "Melts in your hand—boils at a blast furnace." Vedantu educators often use this tip in live sessions to help students recall its unusual melting and boiling points for quick exam reference.
Try This Yourself
- Write the electron configuration of gallium.
- List two real-life uses of gallium compounds.
- Explain why gallium is safer than mercury for use in thermometers.
Final Wrap-Up
We explored gallium—its structure, properties, reactions, and real-life importance. For more in-depth explanations and exam-prep tips, explore live classes and notes on Vedantu.
FAQs on Gallium Element Properties Structure and Applications
1. What is gallium in chemistry?
Gallium is a chemical element with the symbol Ga and atomic number 31. It is a soft, silvery metal belonging to Group 13 of the periodic table.
- Atomic number: 31
- Atomic mass: about 69.72 u
- Block: p-block element
- Common oxidation state: +3
2. What is the electron configuration of gallium?
The electron configuration of gallium (Ga) is [Ar] 3d10 4s2 4p1. This configuration shows that gallium has three valence electrons in the 4th shell.
- Core configuration: [Ar]
- Filled 3d subshell: 3d10
- Valence electrons: 4s2 4p1
3. Why does gallium have a low melting point?
Gallium has a low melting point (about 29.8°C) because of its weak metallic bonding and unique crystal structure. Its melting point is just above room temperature.
- Melting point: 29.8°C
- Gallium atoms form partially covalent bonds in the solid state
- The bonding structure reduces the strength of metallic bonding
4. What are the common oxidation states of gallium?
The most common oxidation state of gallium is +3, although +1 is rare but possible. The +3 state is the most stable due to the loss of three valence electrons.
- Most stable: +3 (forms Ga3+)
- Rare: +1
5. How does gallium react with oxygen?
Gallium reacts with oxygen to form gallium(III) oxide, Ga2O3. The balanced chemical equation is: 4Ga(s) + 3O2(g) → 2Ga2O3(s)
- Product: Gallium(III) oxide
- Oxidation state of Ga: +3
- Type of reaction: Oxidation (redox reaction)
6. Is gallium a transition metal?
Gallium is not a transition metal; it is classified as a post-transition metal in Group 13. Transition metals must have partially filled d-orbitals in their common oxidation states.
- Gallium electron configuration: [Ar] 3d10 4s2 4p1
- The 3d subshell is completely filled (3d10)
- Does not form ions with partially filled d-orbitals
7. What is gallium used for in chemistry and industry?
Gallium is mainly used in the production of semiconductor compounds such as GaAs and GaN. These compounds are essential in electronics and optoelectronics.
- GaAs (gallium arsenide): used in solar cells and high-speed electronics
- GaN (gallium nitride): used in LEDs and laser diodes
- Alloys with low melting points
8. How is gallium extracted from its ores?
Gallium is extracted as a by-product from bauxite and zinc ores during aluminium and zinc processing. It is not mined directly because it occurs in small quantities.
- Obtained from Bayer process liquor in aluminium production
- Separated by electrolysis or chemical precipitation
- Purified by fractional crystallization or zone refining
9. How does gallium react with acids?
Gallium reacts with strong acids such as hydrochloric acid to form gallium(III) salts and hydrogen gas. A balanced example reaction is: 2Ga(s) + 6HCl(aq) → 2GaCl3(aq) + 3H2(g)
- Gallium is oxidized to Ga3+
- Hydrogen ions (H+) are reduced to H2 gas
- Type of reaction: Single displacement (redox)
10. What are the physical properties of gallium?
Gallium is a soft, silvery metal with a low melting point and high boiling point compared to its size. It exhibits several unusual physical properties.
- Melting point: 29.8°C
- Boiling point: about 2403°C
- Density: about 5.91 g/cm3 (at 25°C)
- Expands upon solidification
