Metals and Non–Metals

Elements in the periodic table are divided into metals and non-metals based on their physical characteristics, such as how hard they are and how closely packed their mass is. Metals are typically hard and dense substances used in construction and electronics, while non-metals generally have lower density, lower strength, and break more easily.

Key properties of metals

• Metals conduct heat and electricity easily, making materials like copper ideal for home electrical wires.
• Malleability allows thick pieces of metal like aluminium to be compressed into thin sheets such as food packaging foil.
• Ductility allows heated metals to stretch across long distances into thin wires without breaking.
• Luster allows metals like copper, silver, and gold to reflect light strongly and shine brightly in jewellery.
• High tensile strength gives metals great pulling resistance, and their ability to vibrate produces a ringing sound when hit, as seen in temple bells and iron gates.

Characteristics of non-metals

Non-metals usually have low density and very little hardness, so materials made from them break or shatter when struck rather than flattening. They do not conduct electricity or heat, which is why wooden gates made of carbon, oxygen, and hydrogen do not heat up under sunlight like iron gates do. Non-metals also have very low ductility and low tensile strength, meaning a plastic rope snaps quickly when pulled by force instead of holding firm like an aluminium wire. In addition, non-metals melt at much lower temperatures, which causes a plastic ruler to melt quickly over a candle flame where a metal ruler would not.

Important exceptions

• Sodium and potassium are metals that have very low hardness, so they are soft enough to be sliced easily with an ordinary knife.
• Mercury is a metal with a remarkably low melting point, which allows it to remain a liquid at normal room temperature inside thermometers.
• Diamond is made entirely of carbon, which is a non-metal, yet it displays the brilliant shining luster normally found only in metals.

Elements called metalloids

The periodic table also includes a category known as metalloids, which possess a mixture of properties from both metals and non-metals. Because these unique elements combine traits from both groups, they formed the foundation for the modern electronics industry.