Types of Pure Substances: Element, Metal, Non-metal, Metalloid

Types of Pure Substances: What is the matter? Anything which has mass and occupies space is called matter. Based on the physical state, the matter is classified into three types, i.e., solids, liquids, and gases. On the other hand, based on the chemical composition, the matter is classified into pure substances and mixtures. In this article, you will explore all about types of pure substances, i.e., elements and compounds – their meaning, examples, properties, etc.

What is a Pure Substance?

A material containing only one substance is called a pure substance. Examples: Metals like iron, gold, silver, etc., copper sulphate, oxygen, halogen, etc.

The characteristics of pure substances are:

1. The pure substance contains only one type of particle. These particles are similar to one another and cannot be separated into simpler particles by any physical process.
2. A pure substance has a definite composition that does not change with time.
3. The pure substance is perfectly homogeneous.
4. A pure substance has a definite melting point, boiling point and density.

What are the Types of Pure Substances?

Pure substances are classified into two types.

1. Elements: These are further classified into the following three types.
(a) Metals
(b) Non-metals
(c) Metalloids

2. Compounds: These are further classified into the following two types.
(a) Inorganic compounds
(b) Organic compound

What are Elements?

An element is defined as the simplest form of a pure substance with definite physical and chemical properties and which can neither be broken into nor built from the simpler substances by any chemical or physical method.

But recent studies showed that elements could be broken down into and synthesised from simple substances. Therefore the definition of the element is modified. According to this, the element is defined as a pure substance that contains only one kind of particle. These particles may be atoms or molecules. 

Depending upon the physical and chemical properties, the elements are further classified into the following three types.

(a) Metals
(b) Non-metals
(c) Metalloids

Metals

Metals are the elements that conduct heat and electricity and are malleable and ductile.

Example: Iron, aluminium, copper, silver, gold, platinum, zinc, tin, lead, mercury, etc.

Physical Properties of Metals

Following are the few important physical properties of metals:

1. Metals are generally solid at room temperature. Mercury is an exception which is a liquid at room temperature.
2. Metals have a lustrous appearance, i.e., they have shining surfaces.
3. Metals are malleable, i.e., metals can be beaten into thin sheets. Gold and silver are the most malleable metals.
4. Metals are ductile, i.e., metals can be drawn into wire. Gold is the most ductile metal.
5. Metals are generally hard. But sodium and potassium are exceptionally soft metals.
6. Metals generally have high density. Iridium and osmium have very high densities. 
7. Due to the strong metallic bond, metals have high melting and boiling points. But the melting point of gallium and caesium.
8. Metals are good conductors of heat, i.e., metals have high thermal conductivity. Silver is the best conductor of heat.
9. Due to the presence of electrons, metals allow electricity to pass through them, i.e., metals are good conductors of electricity. 
10. Metals are sonorous, i.e., they produce sound when struck with hard substance.
11. Metals are usually silver or grey in colour. Copper is reddish-brown in colour, while gold has a golden yellow appearance.

Non-metals

Non-metals are the elements that do not conduct heat or electricity and are neither malleable nor ductile but are brittle.

Example: Hydrogen, oxygen, nitrogen, sulphur, phosphorus, chlorine, etc.

Physical Properties of Non-metals

Following are the few important physical properties of non-metals:

1. Non-metals are generally solid or gas at room temperature. Bromine is an exception which is a liquid at room temperature.
2. Non-metals have a non-lustrous appearance, except iodine.
3. These are malleable. But solid nonmetals are brittle.
4. These are non-ductile.
5. These are generally soft, except diamond, an allotrope of carbon, which is the hardest substance.
6. These generally have low density. 
7. Non-metals have high melting and boiling points due to weak intermolecular forces. 
8. Non-metals are bad conductors of heat.
9. Non-metals are bad conductors of electricity except graphite, which is a good conductor of electricity.
10. Non-metals are non-sonorous.
11. Most of the non-metals like hydrogen and oxygen are colourless. The rest of the nonmetals show different colours like sulphur is yellow, phosphorus is white or red, graphite is black, selenium and iodine are greyish white, etc.

Metalloids

The elements which possess the characteristic of both metals and nonmetals are called metalloids. These are also called semi-metals.

Example: Germanium, boron, arsenic, antimony, selenium and tellurium.

What are Compounds?

Compounds are made of two or more elements in a definite ratio by mass. A compound may be defined as the substance obtained by the chemical combination of two or more elements in a definite proportion by mass and can be decomposed by the chemical means into its constituent elements.

Example: Water \(\left( {{{\rm{H}}_{\rm{2}}}{\rm{O}}} \right)\) is a compound containing hydrogen and oxygen elements combined in a fixed proportion of \(2:16\) (atomic mass hydrogen, \({\rm{H = 1u}}\) and atomic mass of oxygen, \({\rm{O = 16}}\,{\rm{u}}\)) or \(1:8\) by weight. It can be decomposed into its constituent elements, i.e., hydrogen and oxygen, by passing electricity through water.

Some other examples of the compound are nitrogen oxide, nitrogen dioxide, carbon dioxide, etc.

Characteristics of Compound

1. A compound is composed of two or more elements combined together chemically in a fixed proportion by mass.
2. The constituent elements of a compound cannot be separated by physical methods.
For example, a compound iron sulphide (FeS) cannot be separated by the magnet as the compound contains iron.
3. A compound is a homogeneous substance.
4. A compound has a fixed set up of physical properties such as density, melting point, boiling point, solubility, etc.
5. The properties of compounds are entirely different from those of their constituent elements.
Example: Water is composed of hydrogen and oxygen elements. Both hydrogen and oxygen are gases, but water is a liquid. Although hydrogen catches fire and oxygen support combustion, water extinguishes fire.
6. The formation of a compound is accompanied by the evolution or absorption of energy.

Types of Compounds

The compounds may further be classified into the following categories:

1. Inorganic compounds: These compounds are obtained from nonliving sources like seawater, rocks, earth crust, etc. These are non-organic in nature and are the compounds of all elements, except those compounds of carbon which are organic in nature. 
   Example: Water \(\left( {{{\rm{H}}_{\rm{2}}}{\rm{O}}} \right),\) Sodium chloride \(\left( {{\rm{NaCl}}} \right){\rm{,}}\) sulphuric acid \(\left( {{{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}} \right),\) calcium carbonate \(\left( {{\rm{CaC}}{{\rm{O}}_3}} \right).\)

2. Organic compounds: These are the compounds containing carbon and few other elements like hydrogen, oxygen, nitrogen, sulphur, halogens, etc. Most of the organic compounds are obtained from plants and animals, and even they can be synthesised.
   Example: Sugar, urea, fats, oils, proteins, methane, benzene, alcohol, etc.

Use of Pure Substances

Elements and compounds are the types of pure substances. All the substance around us is made up of elements. These elements combine in constant proportion to form a compound. Different compounds combine to give mixtures. Therefore, the pure substance becomes the base for all the substances.

Summary

With this article, you are able to recall the meaning and types of pure substance, i.e., element and compound. Elements are further classified into metals, nonmetals and metalloids. Compounds are further divided into organic compounds and inorganic compounds. Now you are able to explain metals, non-metals, metalloid, organic compounds and inorganic compounds, their properties and examples in detail.

FAQs

Q.1. What is a pure substance?
Ans: A material containing only one substance is called a pure substance. Examples: Gold, silver, copper sulphate, oxygen, halogen, etc.

Q.2. What are types of pure substances?
Ans: Pure substances are classified into two types.
(a) Elements: These are further classified into the following three types.
(i) Metals
(ii) Non-metals
(iii) Metalloids
(b) Compound: These are further classified into the following two types.
(i) Inorganic compounds
(ii) Organic compound

Q.3. What are five pure substances?
Ans: Five pure substances are sodium chloride, iron, copper, water, and graphite.

Q.4. What are three examples of pure substances?
Ans: Three examples of pure substances are gold, zinc and sulphur.

Q.5. What are pure substances used for?
Ans: Elements and compounds are the types of pure substances. All the substance around us is made up of elements. These elements combine in constant proportion to form a compound. Different compounds combine to give mixtures. Therefore, the pure substance becomes the base for all the substances.

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