What Are the Properties and Common Uses of Mercury in Chemistry?
Mercury is essential in chemistry and helps students understand various practical and theoretical applications related to this topic. This element stands out due to its unique physical properties and widespread industrial relevance.
What is Mercury in Chemistry?
- A mercury element refers to a metallic chemical element with the symbol Hg and atomic number 80.
- This concept appears in chapters related to transition elements, heavy metal chemistry, and environmental science, making it a foundational part of your chemistry syllabus.
- Mercury is unique for being a liquid metal at room temperature and is also called quicksilver.
Molecular Formula and Composition
The molecular formula of metallic mercury is simply Hg. It consists of just one mercury atom per molecule and is categorized under elemental metals and transition elements. The name "mercury" comes from the Greek “hydrargyrum” meaning liquid silver due to its appearance.
Preparation and Synthesis Methods
Mercury is primarily obtained by the extraction from its main ore, called cinnabar (mercury(II) sulfide, HgS). The industrial method involves roasting cinnabar in air, causing it to decompose into mercury vapor and sulfur dioxide.
The vapor is then cooled and condensed to collect liquid mercury. Besides its natural occurrence, mercury cannot be prepared synthetically in a laboratory due to its status as a naturally occurring element.
Physical Properties of Mercury
Mercury’s physical properties are unique among metals and contribute to its many applications.
| Property | Value |
|---|---|
| Atomic Number | 80 |
| Element Symbol | Hg |
| Physical State at 25°C | Liquid |
| Density (20°C) | 13.6 g/cm³ |
| Melting Point | -38.83°C |
| Boiling Point | 356.6°C |
| Color | Silvery-white |
Mercury does not wet glass, is a good conductor of electricity, and is highly dense compared to other metals. It slowly tarnishes in moist air and forms small beads.
Chemical Properties and Reactions
Mercury displays interesting chemical properties. It is less reactive than many metals yet can form several important compounds.
- It does not react with oxygen at room temperature but combines with it when heated.
- It reacts with concentrated acids and aqua regia.
- Mercury reacts with sulfur to form mercury(II) sulfide (vermilion pigment).
- It forms amalgams when mixed with metals like gold or silver.
A typical reaction is:
2Hg + O2 (heat) → 2HgO (mercury(II) oxide)
Frequent Related Errors
- Confusing mercury with nonmetals or other liquid substances.
- Assuming all metals are solid at room temperature.
- Overlooking the toxic nature of mercury and safe lab precautions.
- Mixing up Hg with other element symbols.
Uses of Mercury in Real Life
Mercury is widely used due to its liquid state and high density. Some everyday and industrial uses include:
- Thermometers and barometers for measuring temperature and pressure
- Electrical switches and relays because it conducts electricity easily
- Fluorescent and mercury-vapour lamps
- Dentistry (historically, in amalgam fillings)
- Gold and silver extraction in mining industries
- Production of certain chemicals and fungicides
Due to its toxicity, mercury usage is now limited or replaced by safer alternatives in many fields.
Relation with Other Chemistry Concepts
Mercury is closely related to topics such as properties of metals and nonmetals and heavy metal pollution. Understanding its position in the periodic table builds connections to electronic configuration, transition metals, and environmental chemistry topics such as pollution and biomagnification.
Step-by-Step Reaction Example
1. Start with the reaction setup.2. Write the balanced equation.
3. Explain each intermediate or by-product.
4. State reaction conditions.
5. Collect products.
Lab or Experimental Tips
Remember that mercury is toxic and vaporizes easily at room temperature—always handle in a well-ventilated lab with gloves. Vedantu educators suggest observing mercury’s bead formation and high density as visual cues during demonstrations.
Try This Yourself
- Write the electron configuration for Hg.
- List two industrial uses of mercury not related to thermometers.
- Explain why mercury is considered harmful to aquatic ecosystems.
Final Wrap-Up
We explored mercury—its structure, properties, reactions, and real-life importance. Mercury’s unique liquid metal state, toxicity, and industrial uses make it significant for chemistry learners. For deeper understanding and exam preparation, refer to live sessions and detailed notes available on Vedantu.
Related Links
FAQs on Mercury (Hg): Properties, Uses, and Safety in Chemistry
1. What is mercury in chemistry?
Mercury is a chemical element with the symbol Hg and atomic number 80. It is the only metal that is liquid at room temperature and is well known for its toxicity and distinctive silvery appearance.
2. Why is mercury liquid at room temperature?
Mercury is liquid at room temperature because of its weak interatomic metallic bonding. Its electrons are tightly bound, preventing the usual free movement seen in solid metals.
3. Where is mercury found in nature?
Mercury is primarily found in the mineral cinnabar (HgS). Key facts include:
- Cinnabar is the main ore of mercury.
- Mercury deposits are found in Spain, Italy, and China.
- Mercury can also exist in the environment through volcanic activity and weathering of rocks.
4. What are the uses of mercury?
Mercury has been widely used in:
- Thermometers and barometers
- Fluorescent lamps
- Dental amalgams (historically)
- Batteries and some industrial processes
5. What are the common compounds of mercury?
Common compounds of mercury include:
- Mercury(II) chloride (HgCl2)
- Mercury(I) chloride (Hg2Cl2)
- Mercury(II) oxide (HgO)
- Mercury(II) sulfide (HgS)
6. Is mercury dangerous to humans?
Yes, mercury and its compounds are highly toxic. Key risks include:
- Damage to the nervous system, kidneys, and other organs
- Particular danger from inhaling mercury vapor
- Organic mercury compounds can cause long-term health effects
7. How is mercury extracted from its ore?
Mercury is extracted by roasting cinnabar (HgS) in air.
- Cinnabar is heated strongly in the presence of oxygen.
- This produces mercury vapor and sulfur dioxide gas.
- The vapor is condensed to collect liquid mercury.
8. What are the forms of mercury found in the environment?
Mercury exists in three forms in the environment:
- Elemental mercury (liquid and vapor)
- Inorganic mercury compounds (like HgCl2)
- Organic mercury compounds (such as methylmercury, a major concern in water contamination)
9. What are the environmental impacts of mercury?
Mercury causes severe environmental pollution. Important points:
- It bioaccumulates in aquatic food chains through biomagnification.
- High levels can harm fish, birds, and humans who consume contaminated seafood.
- Mercury pollution can persist for decades in soil and water.
10. How should mercury be safely handled or disposed of?
Safe handling and disposal of mercury involves:
- Using protective gloves and working in well-ventilated areas
- Avoiding direct contact or inhalation of vapors
- Storing mercury and its compounds in secure containers
- Following local and national hazardous waste disposal rules
11. What are safer alternatives to mercury thermometers?
Safer alternatives include:
- Digital thermometers
- Alcohol-filled glass thermometers
- Galinstan thermometers (non-toxic liquid alloy)
12. What is mercury poisoning and what are its symptoms?
Mercury poisoning occurs when toxic amounts are absorbed by the body. Common symptoms include:
- Tremors and muscle weakness
- Memory loss and mood changes
- Kidney damage
- Difficulty with coordination and vision
