A non-metal does not exhibit the qualities of metal. You cannot define its composition. However, you can consider it by what it doesn’t have. It does not have metallic shine, does not have a high boiling or melting point and does not conduct electricity. You cannot bend it or pound it into any shape. Also, you cannot turn them into a wire or a rod.

Non-metals make up a minority within the periodic table, primarily located on the right-hand side of the table. Hydrogen is the only exception that acts as a non-metal when it is at low pressure and temperature, and it can be found in the upper left of the periodic table. In the presence of high pressure, hydrogen is predicted to be able to function as an Alkali Metal.

Physical Properties of Non-Metals

• Poor conductor of heat and electricity: In contrast to metals, non-metals are poor conductors of electricity and heat other than graphite, which happens to be an excellent conductor of electric current.
• Non-lustrous: Non-metals are not shiny, i.e., they are not lustrous. Iodine and diamond are the exceptions, as they shine in the natural world.
• Sonorous: Non-metals are not sonorous because they don’t produce any ringing sound.
• Brittle: Non-metals are extremely brittle, which implies they are prone to break if stretched or battered and are therefore not malleable or flexible.
• Solid, gas, liquid: Most non-metals are in gaseous states. However, a few non-metals exist in solid and liquid states.
• Low melting point and density: Most non-metals have an extremely low melting point and are low in density.

Chemical Properties of Non-Metals

• Form acidic oxides: Non-metal may form acidic oxides by reaction with oxygen. Non-metal + oxygen creates non-metal oxides, which are acidic in nature.
• Electrons gain: Non-metals can form charged ions by getting their electrons when reacting with the metal.
• 4-8 electrons in the outer shell: In essence, the outer shells of non-metals comprise 4 to 8 electrons. This is why it is prone to draw electrons.
• High electronegativities: We have discovered that in non-metals, there are 4-8 electrons within the outer shell, which means they are more able to absorb electrons. So, it is possible to say that non-metals have high electronegativity.
• Reaction to Water: Non-metals do not react with water, but it is typically very reactive in the air, which is why certain of them are kept in water. For instance, one of the highly reactive non-metal is phosphorus, and it can catch sparks in the presence of air. That is why it is kept in water to stop its exposure to oxygen from the atmosphere.
• Reaction to Bases: The reaction of non-metals with bases is complicated. The reaction of chlorine bases such as sodium hydroxide produces salts like sodium hypochlorite, sodium chloride and water.
• Reaction to Oxygen: The formation of non-metal oxides occurs when oxygen reacts with it. The non-metals oxides are neutral or acidic.

If sulphur reacts with oxygen, it creates sulphur dioxide : S + O2 → SO2.

If sulphur dioxide reacts to water, it produces sulphurous acids :  SO2 + H2O → H2SO3.

Structure of Non-Metals

Non-metals are elements found in the upper-right portion of the periodic table. The behaviours and properties of non-metals differ from the metals that are on the left. In normal conditions, over half of non-metals are gases. One is a liquid, and the remaining comprise some of the softest and toughest solids. Non-metals display a wide range of chemical properties. They are among the least reactive and most reactive elements, and they create a myriad of covalent and ionic compounds.

In many cases, the trends in electronegativity allow us to determine the kind of bonding and physical states of compounds that involve non-metals. We are aware that electronegativity decreases as we progress down a particular group, but it increases when you move between left and right in the span. Non-metals have greater electronegativity than metals.

The compounds created by non-metals and metals are generally ionic due to the vast variations in electronegativity. Metals make cations, non-metals create anions, and the resultant compounds are solid in normal conditions. However, compounds made up of the two non-metals show tiny differences in electronegativity between the atoms and covalent bonding – sharing of electrons – results. They are typically molecular and can be described as liquids, gases or solids that are volatile at press and room temperature.

Uses of Non-Metals

• Chlorine: For purifying drinking water.
• Hydrogen: As rocket fuel.
• Nitrogen: In producing ammonia, nitric acids and fertiliser.
• Sulphur: Preparing sulphuric acid.
• Carbon: Great material to make pencils if it is in graphite form.

Conclusion

Non-metals are elements that don’t exhibit the characteristics of metals. The periodic table contains non-metals placed towards the right side. In the modern periodic table, there are 22 non-metals composed of 10 solid, one liquid, and 11 gases. Carbon, sulphur, phosphorus, iodine, etc., are solid non-metals; bromine is in liquid form; hydrogen, nitrogen, oxygen, chlorine, etc., are gaseous non-metals.