What is Element | Definition, Types, Examples

Element Definition: An element is a pure substance which consists of only one type of atoms/particles. That is, particles of an element consists of only one kind of atoms. These particles may occur as atoms or molecules.

Another definition of elements:

Elements are pure substances that cannot be broken down (or decomposed) into simpler substances by chemical changes or chemical reactions. Each element has a definite atomic number and has a definite position in the periodic table.

Element is the most basic form of matter (or a chemical substance) that exists under ordinary conditions. Sodium, carbon, copper, silver, hydrogen, oxygen, nitrogen, etc., are some familiar examples of elements. Their all atoms are of the same type.

The smallest particles of an element have the same properties as the bigger particles. However, the atoms of different elements occur differently in nature.

Some elements, such as iron, sodium, copper, gold, etc. contain single atoms as their constituent particles held together. Whereas, in some other cases, the constituent particles are molecules which are composed of two or more atoms combined together.

For example, hydrogen, nitrogen, oxygen etc. are gases that consist of molecules, comprising two atoms combined together to give their respective molecules. Look at the below figure to understand better.

Key points of Chemical Elements:

There are the following key points of chemical elements you should keep it up in mind. They are:

• The number of elements known at present are over 115. 92 elements are naturally occurring and the rest are man-made.
• Most of the elements are solid.
• Eleven elements are in a gaseous state at room temperature.
• Two elements, namely mercury and bromine are liquid at room temperature 298 K. Of two liquid, mercury is metal while bromine is a non-metal.
• Two other metals, such as gallium and cesium are also exist at liquid state at a temperature slightly above the room temperature (303 K). Gallium (melting point = 302.9 K and cesium melting point = 301.6 K).

What is Pure Substance?

According to the chemical classification of matter, there are two main families:

• Pure substances
• Mixtures

On the basis of quantitative studies, a French chemist, Lavoisier classified pure substances into elements and compounds. He illustrated that when we heat mercuric oxide; it changes into mercury and oxygen.

Mercury oxide → Mercury + oxide

Here, mercuric oxide is a compound because it breaks down or decomposes into simpler substances, while mercury and oxygen cannot be further broken down into anything simpler because both are elements.

So, a pure substance consists of a single kind of particles. It has a constant composition. For instance, pure water is always 88.81% oxygen by weight. Meaning that the amount of oxygen present in 100 grams of pure water is 88.81 grams, whereas 11.91 grams of hydrogen are present.

Pure substances also have constant physical and chemical properties. For example, water freezes at exactly 0℃ and boils at exactly 100℃ at atmospheric pressure.

Hence, the composition and properties of a pure substance are always the same. No matter where it is found. For instance, the salt (if pure) found in a salt shaker on the dining table has the same composition as the salt dug from the mines deep beneath the earth or the salt obtained from evoprating sea water.

No matter where salt comes from. It always contains 1.54 times as much chlorine by weight as sodium. Since it always has the same composition, salt has the same physical and chemical properties.

Question: Two samples of ammonia (NH₃) are collected, one from the manufacturing plant and another from the urine deposits of animals. Does both samples contain the same composition of nitrogen and hydrogen? If yes, give reason.

Answer: Yes, both samples will contain the same quantity of nitrogen and hydrogen because both samples are pure substance, not a mixture.

Do you know? A solution of salt in water or sugar solution is a homogeneous that contains uniform composition and identical properties throughout. It appears to consist of one type of particles. But, it consists of more than one kind of particles. Hence, it is not a pure substance, a mixture.

Names of Elements

Elements’ names come from various sources. They are as:

• Some chemical element names are derived from Greek, Latin, or German words of colors. For instances, bismuth (white mass), chlorine (greenish-yellow), iridium (rainbow), and rubidium (deep red).
• Some names associate with the locality where the element was discovered. For example, germanium, francium, and californium.
• Four elements, such as yttrium, ytterbium, erbium, and terbium are all named after a town Ytterby in Sweden near where they were discovered.
• Other elements respect famed scientists (e.g., curium, einsteinium, and fermium) or mythological figures (e.g., mercury, plutonium, uranium, and titanium).
• Several of the oldest known elements have names with obscure origins.

Symbols of Elements

There are presently more than 100 different elements known. Every element has given a certain name and, for convenience, a nickname which in chemical language is called a symbol.

A symbol is usually a small abbreviation to represent a full and lengthy name of the element. It usually comprises the first one or two letters of the element’s English or Latin name. Symbols of different elements have been derived:

(i) either by taking the first letter of the element’s name in capital. They are:

• C – Carbon
• O – Oxygen
• P – Phosphorus
• N – Nitrogen
• H – Hydrogen
• S – Sulphur
• F – Fluorine
• U – Uranium
• I – Iodin

(ii) or by taking the first capitalized letter and one more small letter from the element’s name.

• AI – Aluminium
• Br – Bromine
• Bi – Bismuth
• Ca – Calcium
• Mg – Magnesium
• CI – Chlorine
• Ni – Nickel
• Co – Cobalt
• Sa – Barium

(iii) Symbols of some common elements are derived from their original Latin and German names. They are:

• Na – Sodium (Latin name Natrium)
• Cu – Copper (Latin name Cuprum)
• Fe – Iron (Latin name Ferrum)
• Ag – Silver (Latin name Argentum)
• Pb – Lead (Latin name Plumbum)
• Au – Gold (Latin name Aurum)
• K – Potassium (Latin name Kalium)
• Hg – Mercury (Latin name Hydragyrum)
• W – Tungsten (German name Wolfram)

List of Some Common Elements

The below table is a list of some common elements along with their symbols.

List of Man-Made Elements

Out of 118 elements known, 88 elements have originated from natural sources and the remaining have been prepared by artificial means. The man-made elements are as:

From the above table, the elements from 1 to 25 are transuranic elements. Scientist G.T. Seaborg discovered the most of the transuranic elements.

Distribution or Abundance of the Elements on Earth Crust

Most of the earth’s crust has composed of a few elements. Only ten of the naturally occurring elements constitute 99% mass of the earth’s crust, oceans, and atmosphere. Similarly, over 96% of the mass of our human bodies is composed of only four elements: oxygen, carbon, hydrogen, and nitrogen.

A list of the abundance of highly abundant elements in nature is as follows:

• Oxygen (49.5%)
• Silicon (25.7%)
• Aluminum (7.5%)
• Iron (4.7%)
• Calcium (3.4%)
• Sodium (2.6%)
• Potassium (2.4%)
• Magnesium (1.9%)
• Hydrogen (0.87%)
• Titanium (0.58%)
• Chlorine (0.19%)
• Phosphorus (0.12%)
• All other elements (0.4%)

If we consider the entire universe, the universe made up just three elements: hydrogen (90%), helium (9%), and merely a trace of lithium. The remaining elements, such as oxygen, neon, carbon and nitrogen next in order of decreasing abundance is present only 1% at the universe.

Types/Classification of Elements

Based on the variation in their physical and chemical properties, we can classify all the elements into three groups. They are:

• Metals
• Non-metals
• Metalloids

Metals are one of the most essential elements in our daily life. Sodium, potassium, calcium, aluminium, copper, gold, silver, zinc, iron, nickel, mercury, etc., are the examples of metals.

The general properties of metal elements are as follows:

• Most of the metals are solids at room temperature, with the exception of mercury and gallium. Mercury and gallium are liquids at room temperature.
• They are lustre (shine) in nature.
• Metals possess high density, and they are heavy.
• Metals are good conductors of heat and electricity because they have free electrons.
• They are malleable. We can hammer into a thin sheet known as foils.
• Metals are ductile that can be drawn into wires.
• They possess normally high melting and boiling points.
• They react with mineral acids liberating hydrogen.
• They form basic oxides and non-volatile hydrides if combine with hydrogen.

Non-metals show a wide range of physical and chemical properties. Six non-metals, such as carbon, boron, phosphorus, sulphur, selenium and iodine, are solids. Bromine is the only non-metal that is a liquid at room temperature and normal pressure.

The remaining non-metals, such as hydrogen, helium, oxygen, nitrogen, fluorine, chlorine, argon, neon, krypton, xenon and radon, are gases. Non-metals generally show the following properties. They are:

• Brittle
• Non-lustrous,
• Having low melting and boiling points
• Bad conductors of heat
• Generally form acidic oxides or neutral oxides with oxygen.
• Have the ability to gain electrons easily.

Metalloids are those elements which have some properties of both metals and non-metals. Examples of semi-metals are boron, silicon, germanium, arsenic, antimony and tellurium. The general properties of metalloids are as:

• Metalloids can be shiny as metals and dull like non-metals.
• They are usually brittle and ductile in nature.
• They have metallic lustre.
• Most of the metalloids are semi-conductors.

Frequently Asked Question based on Element Definition