Non-metals: Introduction, Physical and Chemical Properties, Uses, Practice Problems & FAQs

In our workplace or shed, we frequently group parts according to their shared characteristics. The screws might fit in a single container (possibly subdivided by size and type). Nuts storage would be another container. Perhaps there are some drawers for plumbing supplies.

You can also have a collection of items that don't neatly fall into any particular category. You describe what they are not in terms of what they are. They are not parts for a car, sprinkler heads for the lawn, or electrical components. These components come in a variety of forms, yet they may have some characteristics.

These "spares" would be classified as nonmetals in the chemical world, which is broadly defined as not having the properties of metals.

In this article, we will discuss in detail about non-metals, properties of non-metals and uses of non-metals.

Table of contents

Introduction of Non-metals
Physical Properties of Non-metals
Chemical Properties of Non-metals
Uses of Non-metals
Practice Problems
Frequently Asked Questions-FAQs

Introduction of Non-metals

Elements that gain electrons (while forming an electrovalent bond) or share electrons (while forming a covalent bond) are known as non-metals. In their outermost shell, they frequently include 4, 5, 6, or 7 electrons. Non-metals are substances lacking all the qualities of metals. A non-metal is an element that often conducts heat and electricity. Most of the non-metal qualities are the opposite of a metal's. Non-metals can be found in all three states of matter. Gases are in the majority like nitrogen, oxygen etc. Bromine non-metal is in the liquid state. Only a few of them are solids, like sulphur and carbon. Non-metals are fragile in the solid state, meaning that a hammer blow will cause them to break. The non-metals which are in a solid state don't have much lustre. The elements which are highlighted in green colour in the periodic table are non-metals.

Physical properties of Non-metals

Non-metals have high electronegativity and ionisation energy. Because of these characteristics, non-metals typically gain or share electrons while interacting with other elements to form either ionic or covalent bonds.

Most of the time, non-metal atoms are smaller than metal atoms. Numerous other features of non-metals are governed by their atomic sizes.

Non-metal’s electrical conductivities are exceedingly low. The most essential distinction between non-metals and metals is their low or non-existent electrical conductivity. They are poor heat and electricity conductors, with the exception of graphite which is a good conductor of electricity. .

Under normal temperature and pressure, certain non-metals exist as gases, some are solids, and one is a liquid. For example; oxygen, and nitrogen exists in gaseous form while bromine exists in liquid form and carbon exists in solid form.

Non-metals are prone to becoming brittle in their solid state. As a result, they lack metal's malleability and ductility. The ability of a material to be pulled into wires is known as ductility. Non-metals are not ductile, with the exception of carbon, which is employed in a variety of industries Non-metals lack the property of malleability, which is specific to metals. They are brittle and break under pressure, thus they cannot be drawn into sheets.

They don't make a deep ringing sound or a sonorous sound when they collide with another material.

The top right corner of the periodic table contains the non-metals that are the most reactive. The non-metal with the maximum reactivity is fluorine. It doesn't occur as a free element in nature. One of the most dangerous substances known, fluorine gas interacts explosively with a range of other elements and compounds. Fluorine is the most chemically reactive and electronegative element of all, and it is a poisonous univalent gaseous halogen with a colour of pale yellow-green.

Gold, silver, and copper are examples of metals that can be polished and have the capacity to reflect light from their surfaces. On the other hand, non-metals do not shine. They don't have a reflective surface. Non-metals appear gloomy, whereas metals have a sparkling appearance. Though the two sparkling non-metals outliers are diamond and iodine.

Chemical Properties of Non-metals

Reaction with oxygen:

On heating, non-metals generate oxides when they interact with oxygen. These oxides may be neutral or acidic in nature. They don't produce basic oxides. When non-metal oxides are dissolved in water, acids are produced.

Carbon dioxide is produced when carbon burns in the presence of excessive air and carbonic acid is formed when carbon dioxide dissolves in water.

C(s) + O₂(g) → CO₂(g)

CO₂ (g)+ H₂O(l) → H₂CO₃(aq)

Reaction with water:

Non-metals typically don't combine with water to generate hydrogen gas. This is so because non-metals are unable to convert water's hydrogen ions into hydrogen gas. However, some non-metals with strong reactivity, like fluorine, react with water to produce oxygen or ozone molecules.

2F₂ (g)+ 2H₂O(g) → 4HF(l) + O₂(g)

3F₂(g) + 3H₂O(g) → 6HF(l) + O₃(g)

Reaction with salt solutions:

A much more reactive non-metal typically pushes a less reactive non-metal out of its salt solution.

An illustration of this is the formation of sodium chloride and bromine gas when chlorine gas is passed through a solution of sodium bromide.

Cl₂(g) + 2NaBr(aq) → 2NaCl(aq)+ Br₂(l)

Reaction with chlorine:

Covalent chlorides are usually created when non-metals react with chlorine.

As an illustration, hydrogen and chlorine react to produce hydrogen chloride gas when exposed to scattered sunlight.

Cl₂(g) + H₂(g) → 2 HCl(g)

As an illustration, at 713 K, hydrogen combines with liquid sulphur to produce hydrogen sulphide gas.

H₂(g) + S(g) → H₂S(g)

Reaction with dilute acids:

Since non-metals do not remove hydrogen from acids, they do not combine with diluted acids. This is so that a nonmetal, which is an electron acceptor, cannot reduce hydrogen ions to hydrogen gas by supplying electrons to them.

Reaction with metals:

With other atoms, non-metals frequently acquire or share electrons. They have an electronegative character. When non-metals interact with metals, they often gain electrons to acquire the stable electronic configuration of noble gas and transform it into anions.

3Cl₂(g)+ 2Al (s)→ 2AlCl₃(s)

Uses of Non-metals

In order to make ammonia, nitric acid, and fertilisers, nitrogen is used.

For the purpose of purifying water, chlorine is utilised.

Superb rocket fuel is hydrogen.

Pencils can be made from carbon when it is in graphite form.

Nonmetals are used for a wide range of things. Gunpowder, fireworks, and matches can all use sulphur to help them ignite. This substance is frequently used as a pesticide, disinfectant, or to get rid of specific kinds of fungi. The production of rubber for tyres and other products is one of the sulphur's major uses. The vulcanization process, which Charles Goodyear first developed in 1839, increases the rubber's flexibility, elasticity, and resistance to temperature changes. Making sulphur-containing chemicals like sulfuric acid is one of the main uses of sulphur.

Bromine is a versatile substance that is mostly utilised in the production of flame-resistant textiles, which is crucial for children's clothes. Due to its better effectiveness, bromine is starting to take the role of chlorine in the treatment of water in hot tubs and swimming pools. Bromine atoms serve significant roles in medications for the treatment of pain, cancer, and Alzheimer's disease when they are included in compounds.

One of the numerous nonmetals that are gases is helium. Hydrogen, fluorine, chlorine, and all of the group 18 noble (or inert) gases are examples of additional nonmetal gases. Helium is excellent for applications like balloons and lasers, where non-flammability is crucial because it is chemically non-reactive. At very low temperatures, liquid helium can be utilised to cool superconducting magnets for imaging research (MRI, magnetic resonance imaging). Helium can be used to find leaks in vessels and various high-vacuum equipment. When you breathe in helium, the speed of sound is altered, raising the pitch of your voice. This is undoubtedly a dangerous activity that might cause harm to one's body or perhaps death.

Practice Problems:

Q1. Non-metals are:

(A) good oxidising agents
(B) good reducing agents
(C) both oxidising and reducing agents
(D) None of the above

Answer: (A)
Solution: Non-metals function as oxidising agents because they take up electrons in their outermost shell, and oxidise other elements. Non-metals are electronegative in nature and readily form anions due to their propensity to gain electrons. Non-metals have the ability to oxidise themselves by taking up electrons, making them good oxidising agents.

For example: $C l_{2} + {2 e}^{-} \to {2 C l}^{-}$

Q.2. Reaction of sulphur with oxygen forms:

(A) Acidic oxide
(B) Basic oxide
(C) Amphoteric oxide
(D) All of these

Answer: (A)

Solution: Sulphur dioxide is produced when sulphur reacts with the oxygen in the presence of excessive air and sulphurous acid is formed when sulphur dioxide dissolves in water.

$S (s) + O_{2} (g) \to 〖 S O 〗_{2} (g)$

${S O}_{2} (g) + H_{2} O (l) \to H_{2} {S O}_{3} (a q)$

Q.3. Out of the following options, which is an acidic oxide?

(A) CO
(B) NO
(C) SO₃
(D) H₂O

Answer: (C)
Solution: H₂O, NO and CO are neutral oxides. Sulphur is a non-metal, producing sulphur trioxide (SO₃) on reaction with oxygen which is an acidic oxide by nature. Sulphuric acid is formed when this oxide dissolves in water.

${S O}_{3} (g) + H_{2} O (l) \to H_{2} {S O}_{4} (a q)$

Q.4. The substance utilised in computers, televisions etc. because of its semiconductor qualities is:

(A) Carbon
(B) Silicone
(C) Fluorine
(D) Bromine

Answer: (B)
Solution: Unique materials known as semiconductors have electrical conductivity value between insulators and conductors. Semi-conductors are made of pure silicon crystal. Due to its four valence electrons, silicon is ideal for creating this lattice structure since it can precisely connect to four of its silicon neighbours.

Frequently Asked Questions - FAQs

Q1. Why is oxygen categorised as a non-metal?
Answer: On Earth, oxygen has many unique and mystical qualities and uses. Because oxygen belongs to the chalcogen group on the periodic table, it is classified as a highly reactive non-metallic element. Without the photosynthetic function of living creatures, oxygen in its free state is chemically reactive and cannot exist on Earth. This process employs sunlight as a source of energy to create elemental oxygen from water.

Q2. How can we tell whether an element is a metal or a non-metal?
Answer: It is carried out based on its valency. When forming cations, metals may lose or give electrons. In their outermost shells, they have 1, 2 or 3 electrons. Giving away 1, 2 or 3 electrons makes it simpler for them to generate an entire octet than taking more than 4 electrons. Consequently, the charges on metals are +1, +2, +3. This type of behaviour is referred to as a metallic character.

Additionally, elements having 5, 6 and 7 electrons in their valence shell prefer to take electrons and form anions. Therefore anions attain charges of -3, -2 and -1 respectively. This type of behaviour is referred to as a non-metallic character.

Q3. Why are non-metals poor electrical conductors and metals good electrical conductors of electricity?
Answer: The majority of metals are effective electrical conductors. This occurs because the outermost electrons lose contact with their parent atoms when metal atoms unite with one another. While the outside electrons circulate freely throughout the entire metal crustal, the remaining positively charged atomic centres organise themselves into an ordered structure. Hence, metals are good conductors of electricity.

The nucleus of non-metals, on the other hand, securely holds the conduction electrons. As a result, they are immobile. Because they lack free electrons, non-metals are therefore regarded as weak electrical conductors.

Q4. What are Metalloids?
Answer: The characteristics of metalloids are in-between those of metals and non-metals. The semiconductor industry can benefit from metalloids. At normal temperature, all metalloid particles are solid. They can combine with other metals to make alloys. Under the proper circumstances, several metalloids, like silicon and germanium, can function as electrical conductors; for this reason, they are referred to as semiconductors. For instance, silicon has a glossy appearance but is neither malleable nor ductile (it is brittle - a characteristic of some nonmetals). Compared to metals, it is a far worse conductor of heat and electricity. Metalloids typically have non-metallic chemical properties but metallic physical qualities.