Metals and Non-Metals
- Consider trying to bend a metal spoon and a piece of chalk.
- The spoon flexes a little, but the chalk snaps in two.
- These contrasting behaviours illustrate the fundamental differences between metals and non-metals, two broad categories of elements with distinct properties.
- Most of the elements in the periodic table are metals.
- Non-metals, although fewer in number, play crucial roles in areas such as biochemistry, materials science and electronics.
Note
In both MYP and IB Chemistry you will often begin studying an element by asking:
Is it a metal, non-metal or metalloid?
Note
- Elements that show properties of both metals and non-metals are called metalloids.
- Common examples include boron, silicon and arsenic (B, Si, As).
- Metalloids are found along the zig-zag line on the right-hand side of the periodic table, separating most metals from most non-metals.
Hint
If you are unsure about terms such as solid, liquid, gas or density, review the article on states of matter and related concepts before continuing.
Self review
- How many metals and non-metals can you name from memory?
- Where are metals, non-metals and metalloids usually found on the periodic table?
Physical Properties of Metals
Most metals share the following physical properties:
- Shiny (lustrous):
- They reflect light.
- A polished silver spoon or a new aluminium can is a good example.
- Good conductors of electricity and heat:
- Metals such as copper are used in electrical wiring because they allow electric current and heat to pass through them easily.
- Malleable:
- They can be hammered or rolled into thin sheets without breaking.
- Aluminium foil is a familiar example of a very thin metal sheet.
- Ductile:
- They can be stretched (drawn) into wires.
- Gold, for example, can be drawn into extremely thin wires.
- High melting and boiling points:
- Most metals are solid at room temperature and melt only at high temperatures (the main exception you will meet is mercury, which is a liquid at room temperature).
- High density:
- Many metals, such as iron and lead, feel heavy for their size.
- Sonorous:
- They produce a ringing sound when struck (for example, a metal bell or a school gong).
Note
All of the above are general trends; IB will expect students later to know that some metals (e.g. Group 1) have relatively low melting points and densities, so you might occasionally flag that these are “usually, but not always” true.
Example
- Copper wires power your home, while iron is used to construct buildings and bridges.
- Gold and silver are used in the production of jewelry.
Physical Properties of Non-Metals
In contrast, many non-metals show the opposite pattern of properties:
- Dull:
- They usually lack the shine of metals.
- For example, solid sulfur and carbon (charcoal) appear dull.
- Poor conductors:
- Most non-metals are insulators, meaning they do not conduct heat or electricity well.
- This makes them useful for covering wires (plastic) or insulating buildings (foam, fibreglass).
- Brittle (when solid):
- Solid non-metals tend to break or shatter when hit, rather than bend.
- Lower melting and boiling points:
- Many non-metals are gases at room temperature (for example oxygen and nitrogen), and several solid non-metals melt or boil at relatively low temperatures compared with metals.
- Lower density:
- Non-metals are often lighter than metals.
- For example, gases like oxygen are much less dense than solid metals such as copper.
Note
- Carbon is a non-metal, but in its graphite form it can conduct electricity.
- Graphite is made of layers of carbon atoms arranged in hexagons.
- Electrons can move freely within each layer, allowing electrical conduction.
- This is an important reminder that not all non-metals are insulators.
Example
- Carbon in graphite form is used in pencils.
- Sulfur is used in the production of fertilizers.
Comparing Physical Properties
The table below summarizes the physical properties of metals and non-metals:
| Property | Metals | Non-metals |
|---|---|---|
| State at room temperature | Mostly solids (except mercury, which is liquid) | Solids, liquids (bromine), and gases (e.g. O₂, N₂, Cl₂) |
| Appearance | Shiny, lustrous | Dull (if solid), not shiny |
| Density | Usually high density | Often low density (many are light elements) |
| Hardness | Generally hard (except e.g. sodium, potassium) | Many are soft or brittle when solid |
| Malleability | Malleable – can be hammered into sheets | Brittle if solid – shatter or crumble when hit |
| Ductility | Ductile – can be drawn into wires | Not ductile |
| Electrical conductivity | Good conductors of electricity | Poor conductors (insulators), except graphite |
| Thermal conductivity | Good conductors of heat | Poor conductors of heat |
| Melting & boiling points | Usually high | Often low (especially for molecular non-metals) |
| Sound when struck | Sonorous (ringing sound) | Not sonorous |
Common Mistake
- “All metals are magnetic.” → Only a few common metals (iron, nickel, cobalt and some of their alloys) are magnetic.
- “All metals are hard and strong.” → Some metals (like sodium and potassium) are soft and can be cut with a knife.
- “All non-metals are gases.” → Many non-metals are solids (like carbon, sulfur and phosphorus), and bromine is a liquid non-metal.
Chemical Properties of Metals
Metals show some characteristic patterns in their chemical behaviour. In many reactions, metals tend to:
- Lose electrons:
- Metal atoms lose one or more electrons to form positive ions (cations).
- Example: A sodium atom (Na) loses one electron to form a sodium ion (Na⁺).
- React with oxygen:
- Metals react with oxygen to form metal oxides, which are usually basic. $$2Mg (s) + O_2 (g) → 2MgO (s)$$
- React with acids:
- Many metals react with dilute acids to form a salt and hydrogen gas. $$Zn (s) + 2HCl (aq) → ZnCl_2 (aq) + H_2 (g)$$
- React with water:
- Some metals react with water to produce a metal hydroxide and hydrogen gas. $$2Na (s) + 2H_2O (l) → 2NaOH (aq) + H_2 (g)$$
- This reaction is vigorous and exothermic, especially for reactive metals like sodium and potassium.
- Many less reactive metals (e.g. copper, gold) do not react with cold water.
Chemical Properties of Non-Metals
Non-metals usually show a different pattern of chemical behaviour. They tend to:
- Gain or share electrons:
- Non-metal atoms gain electrons to form negative ions (anions), or share electrons to form covalent bonds.
- For example, a chlorine atom ($Cl$) gains one electron to form a chloride ion ($Cl^-$).
- In molecules like water ($H_2O$), non-metals share electron pairs.
- React with oxygen:
- Non-metals react with oxygen to form non-metal oxides, which are usually acidic. $$C (s) + O_2 (g) → CO_2 (g)$$
- Carbon dioxide dissolves in water to form a weak acid (carbonic acid), which is why we call $CO_2$ an acidic oxide.
- Do not react with acids (in the same way as metals):
- Non-metals do not displace hydrogen from dilute acids, so they do not typically produce hydrogen gas when added to an acid.
- Take a note that reactions of non-metals with strong oxidising acids are beyond the scope of MYP.
- React with metals:
- Non-metals can react with metals to form ionic compounds.
- The metal loses electrons and the non-metal gains them. $$2Na (s) + Cl_2 (g) → 2NaCl (s)$$
Comparing Chemical Properties
The table below highlights the chemical differences between metals and non-metals:
| Property | Metals | Non-metals |
|---|---|---|
| Tendency to gain/lose electrons | Tend to lose electrons to form positive ions (cations) | Tend to gain electrons or share electrons; form anions or covalent bonds |
| Typical ions formed | Cations (e.g. Na⁺, Ca²⁺, Al³⁺) | Anions (e.g. Cl⁻, O²⁻) or neutral molecules (e.g. O₂, N₂) |
| Reaction with oxygen | Form basic metal oxides (e.g. MgO, CaO) | Form acidic or neutral oxides (e.g. CO₂, SO₂, N₂O, NO₂) |
| Reaction with water | Many react to form metal hydroxides + hydrogen (e.g. Na, K, Ca) | Most do not react with water |
| Reaction with acids | Many react with acids → salt + hydrogen gas (if above H in reactivity series) | Non-metals generally do not react with dilute acids to give H₂ |
| Reaction with bases | Usually little or no reaction with alkalis | Acidic non-metal oxides react with bases to form salts + water |
| Nature of oxides | Mostly basic oxides | Mostly acidic or neutral oxides |
| Position in redox reactions | Often acts as reducing agents (get oxidized) | Often act as oxidizing agent (get reduced) |
| Corrosion / oxidation tendency | Many corrode or tarnish (e.g. rusting of iron) | Many are resistant to corrosion in elemental form |
Hint
- The ability to lose or gain electrons is central to the reactivity of metals and non-metals.
- This idea links directly to ion formation and to the differences between ionic and covalent bonding.
Exceptions and Metalloids
- Not all elements fit neatly into the categories of “metal” or “non-metal”.
- Some elements show a mixture of both metallic and non-metallic properties.
- These are called metalloids (or semi-metals).
Example
Common examples include:
- Silicon (Si):
- Shiny like a metal
- Brittle, so it breaks rather than bends
- A poor conductor at low temperatures but a better conductor when heated or when impurities are added → this “in-between” behaviour is typical of a semiconductor.
- Arsenic (As):
- Can conduct electricity
- Brittle and not malleable like typical metals
Note
- Metalloids such as silicon and germanium are widely used in semiconductors inside electronic devices (computers, smartphones, solar cells).
- Their ability to conduct electricity under certain conditions makes them ideal for controlling electric currents.
Real-World Applications of Metals and Non-Metals
Why Metals are Widely Used?
The unique physical and chemical properties of metals make them extremely useful in many areas:
Example
- Electrical wiring:
- Metals like copper and aluminium are used in electrical cables because they have high electrical conductivity and are ductile (can be drawn into wires).
- Copper wires carry electricity in homes, schools and industries
- Construction:
- Steel (an alloy containing iron) is strong, malleable and relatively resistant to corrosion.
- It is used in building bridges, skyscrapers, pipelines and many other structures
- Jewellery and currency:
- Metals such as gold, silver and platinum have high lustre, are resistant to tarnishing and are relatively unreactive.
- They are used in jewellery, high-value coins and as investment metals.
- Transportation:
- Aluminium is lightweight and corrosion-resistant, so it is used for aircraft bodies, some car parts and drink cans.
- Steel is used in car frames, train tracks and shipbuilding because of its strength.
- Cookware:
- Metals such as stainless steel and aluminium are good conductors of heat, making them ideal for pots, pans and other kitchen utensils.
Why Non-metals are Essential for Life and Technology?
Non-metals are just as important as metals. They play vital roles in living organisms and in modern technology.
Example
- Life processes:
- Elements such as carbon (C), hydrogen (H), oxygen (O) and nitrogen (N) are the main building blocks of organic molecules (like DNA, proteins, carbohydrates and fats).
- Oxygen is essential for cellular respiration.
- Carbon forms the backbone of the complex molecules of life.
- Insulation:
- Many non-metallic materials (such as plastics, rubber and glass) are poor conductors of electricity and heat, so they are used as insulators in electrical wiring, plugs, and building materials.
- Fertilisers and chemicals:
- Non-metals like nitrogen, phosphorus and sulfur are key components of fertilisers, helping plants grow.
- Sulfur is also used to produce sulfuric acid (H₂SO₄), one of the most important industrial chemicals.
- Water purification:
- Chlorine (Cl₂) is used in small amounts to disinfect drinking water, killing harmful bacteria and other microorganisms.
- Gas applications:
- Hydrogen can be used in fuel cells to produce clean energy (water is the only product).
- Helium is used to fill balloons and as a cooling gas in certain types of scientific and medical equipment.
- Everyday products:
- Sulfur is used in the vulcanisation of rubber, which makes tyres tougher and more durable.
- Oxygen is stored in tanks for medical use and for industrial processes such as welding.
Predicting Properties from the Periodic Table
The position of an element on the periodic table gives strong clues about whether it is a metal, non-metal or metalloid, and helps predict its likely properties.
Where are Metals Located?
Metals dominate the periodic table:
- Left and centre:
- Most elements on the left and in the centre of the periodic table are metals.
- Groups 1 and 2:
- These are the alkali metals (Group 1) and alkaline earth metals (Group 2).
- They are generally very reactive metals.
- Transition metals (Groups 3–12):
- Found in the central block, these metals often show:
- Variable oxidation states
- Formation of coloured compounds
- Use as catalysts (e.g. iron in the Haber process).
- Found in the central block, these metals often show:
Note
Hydrogen is placed in Group 1 but it is a non-metal. Its position is based on electron configuration rather than metallic character.
Where are Non-Metals Located?
Non-metals are mostly found on the right-hand side of the periodic table:
- Groups 14–18:
- Many non-metals are found here, including carbon (C), nitrogen (N), oxygen (O) and sulfur (S).
- Halogens (Group 17):
- Fluorine, chlorine, bromine, iodine and astatine are all non-metallic and very reactive.
- Noble gases (Group 18):
- Helium, neon, argon, krypton, xenon and radon are non-metals with very low reactivity due to their full outer electron shells.
What are Metalloids and Where are They Located?
Metalloids form a diagonal “staircase” line between metals and non-metals:
- Elements such as boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb) and tellurium (Te) are often classified as metalloids.
- They share properties of both metals and non-metals:
- Often brittle like non-metals
- Can conduct electricity better than non-metals, but not as well as good metals
- Many act as semiconductors, making them very important in electronics and computer technology.
Exam technique
By knowing where an element is located on the periodic table (left, right, or along the staircase), you can often predict whether it is likely to be a metal, non-metal or metalloid, and what some of its properties might be.
Note
In IB Chemistry you will study in more depth how the periodic table helps you predict:
- Metallic vs non-metallic character across a period and down a group
- Trends in ionisation energy, electronegativity and atomic radius
- How these trends explain why metals lose electrons and non-metals gain or share electrons
Building a strong understanding now of where metals, non-metals and metalloids are located will make those later topics much easier.
