Grade 9 ↓
Metals and Nonmetals
In the study of chemistry, elements are divided into two main categories: metals and nonmetals. Understanding the difference between metals and nonmetals is fundamental to the study of chemistry and understanding how different substances interact and form compounds. In this article, we will explore the properties, characteristics, and examples of metals and nonmetals.
What are metals?
Metals are elements that are generally hard, lustrous, malleable, and good conductors of electricity and heat. Most metals are solid at room temperature, except mercury, which is a liquid. Metals lose electrons in reactions and form positive ions. Metals are shown on the left-hand side of the periodic table.
Properties of metals
Metals have specific physical and chemical properties, based on which they can be identified and classified. These include:
- Conductivity: Metals are excellent conductors of electricity and heat. This is why materials like copper and aluminum are used in electrical wires.
- Lustre: Metals are shiny. This is called metallic lustre and is the reason why metals are used in jewellery.
- Malleability: Metals can be drawn into thin sheets without breaking. For example, gold can be made so thin that it becomes transparent.
- Ductility: Metals can be stretched into wires. This property is essential for making cables and other flexible electrical connections.
- Density: Most metals have a high density, which means they are heavy for their size. Osmium and iridium are among the densest metals.
- High melting and boiling points: Metals generally have high melting and boiling points. For example, tungsten has the highest melting point of any metal.
Chemical properties of metals
- Reactivity: Metals lose electrons in chemical reactions and form cations, such as sodium (
Na
) loses an electron to formNa+
. - Corrosion: Metals like iron corrode when they come in contact with water and oxygen, resulting in corrosion.
Examples of metals
Let's look at some common metals and examples of their uses:
- Iron (Fe): Used in construction, vehicles, and tools.
- Aluminum (Al): Light and strong, used in aircraft construction and food packaging.
- Copper (Cu): Used in electrical wiring and plumbing due to its excellent conductivity.
Visual example: atomic structure of a metal
What are nonmetals?
Nonmetals are elements that do not typically have the properties of metals. They are found on the right side of the periodic table. Nonmetals are distinct in being poor conductors of heat and electricity, and they are not ductile or malleable. Instead, they are brittle when solid and most exist as a gas at room temperature.
Properties of non-metals
- Poor conductors: Non-metals are generally poor conductors of heat and electricity. This is why they are used as insulators.
- No luster: Nonmetals do not have a metallic luster; instead, they appear dull.
- Brittle: Solid nonmetals, such as sulfur, break or shatter when hammered.
- Low Density: Many nonmetals have lower densities than metals.
- Low melting and boiling points: Non-metals generally have low melting and boiling points. For example, oxygen has a very low boiling point.
Chemical properties of nonmetals
- Electronegativity: Nonmetals gain electrons to form anions. For example, chlorine gains electrons to form
Cl-
- Reactivity: Nonmetals often form covalent bonds by sharing electrons with other atoms.
- Oxidizing agents: Nonmetals like oxygen are good oxidizing agents.
Examples of nonmetals
Here are some common nonmetals and their uses:
- Oxygen (O): Necessary for respiration in most organisms.
- Carbon (C): Found in all life forms and is a fundamental component of organic chemistry.
- Nitrogen (N): It makes up 78% of the Earth's atmosphere and is important for protein synthesis in plants and animals.
Visual example: atomic structure of a nonmetal
Difference between metals and nonmetals
For a clear understanding, let's compare metals and non-metals:
Property | Metals | Non-metallic |
---|---|---|
Conductivity | Good conductors of heat and electricity | Bad conductor |
Growability | Flexible | Brittle (when solid) |
Condition at room temperature | Mostly solid (except mercury) | Can be solid, liquid, or gas |
Electron behavior | Tendency to lose electrons | Tendency to gain or share electrons |
Aura | Shiny | Moody |
Metalloids
Metalloids or semi-metals have properties that are intermediate between metals and nonmetals. They are found along the zig-zag line separating metals and nonmetals on the periodic table. Examples include silicon and germanium, which are used as semiconductors in electronics.
Properties and examples of metalloids
- Silicon (Si): Known for its important role in electronics and computer chips.
- Arsenic (As): Used in some metal alloys and as a doping agent in semiconductors.
- Semiconductivity: Metalloids can conduct electricity better than nonmetals, but not as well as metals. Their conductivity can be affected by temperature and other conditions.
Visual example: position of metalloids on the periodic table
In summary, understanding the difference between metals, non-metals and metalloids is important in exploring the periodic table and the behavior of different elements in various chemical reactions. These fundamental classifications form the basis for studying more complex chemical processes and applications in various fields of science and industry.