Elements and symbols play a fundamental role in the field of chemistry. An element is a pure substance composed of atoms that all have the same number of protons in their atomic nuclei. These atoms are considered the building blocks of matter and cannot be further divided into simpler units by ordinary chemical means. Each element possesses unique properties that distinguish it from other elements.

The periodic table of elements is a visual representation that organizes all known elements based on their atomic number, electron configuration, and recurring chemical properties. Currently, there are over one hundred known elements, with new elements occasionally being discovered or synthesized through scientific research.

Each element is assigned a symbol, which is a one or two-letter abbreviation derived from its name. These symbols are universally used in scientific literature and chemical equations to represent elements. For example, hydrogen is represented by the symbol “H,” oxygen by “O,” and carbon by “C.” The symbols provide a concise and standardized way of referring to elements, facilitating communication and understanding among scientists and researchers across the globe.

The study of elements and their properties is crucial for understanding the behavior of matter and the interactions between different substances. Elements are classified into various groups and periods based on their chemical and physical characteristics. These classifications aid in predicting the behavior and properties of elements, as well as their reactions with other elements and compounds.

Elements can exist in different states of matter, such as solids, liquids, or gases, depending on factors such as temperature and pressure. They can also form chemical bonds with other elements, leading to the formation of compounds. The understanding of elements and their interactions is fundamental in fields like materials science, biochemistry, pharmacology, and environmental science, among others.

In summary, elements are the basic building blocks of matter, and each element is characterized by its unique properties. The periodic table provides a systematic arrangement of elements based on their atomic properties. Symbols assigned to each element simplify communication and notation in scientific contexts. The study of elements and their behavior is vital for understanding the nature of matter and its transformations, enabling advancements in various scientific disciplines.


There are three ways in which symbols of elements are derived.

  1. From the first letter of the name of the element

Element                                         Symbols

Hydrogen                                          H

Oxygen                                               O

Iodine                                                 I

Fluorine                                              F

Nitrogen                                            N

Sulphur                                             S

Carbon                                              C

Phosphorus                                     P

  1. The first letter is capital letters and one other letter from its name is written in small letters.

Element                                    Symbol

Chlorine                                    Cl

Bramine                                    Br

Calcium                                    Ca

Aluminium                                Al

Magnesium                               Mg

Berylium                                   Be

Helium                                       He

Neon                                          Ne

Lithium                                     L


  1. The symbols of some elements were derived from their Latin names.

Elements          Latin name                   Symbols

Mercury            Hydragyrium                Hg

Sodium            Natrium                        Na

Iron                  Ferrum                         Fe

Copper             Cuprum                        Cu

Silver                Argentum                     Ag

Tin                   Stannum                      Sn

Gold                 Aurum                          Au

Potassium        Kalium                          K

Lead                 Plumbum                     Pb


Elements can be broadly classified into two main categories: metals and non-metals. This classification is based on the characteristic properties exhibited by these elements.

Metals are elements that typically have shiny surfaces, are good conductors of heat and electricity, and tend to be malleable and ductile. They are often solid at room temperature, with the exception of mercury, which is a liquid. Metals tend to have high melting and boiling points compared to non-metals. They are generally found on the left and middle sections of the periodic table.

Some examples of metals include iron, zinc, tin, aluminum, copper, silver, gold, and lead. Iron is a widely used metal in construction and manufacturing, while copper is known for its excellent electrical conductivity. Aluminum is lightweight and corrosion-resistant, making it suitable for applications in aerospace and packaging industries. Metals like gold and silver are prized for their luster and resistance to oxidation, making them valuable in jewelry and currency.

On the other hand, non-metals are elements that typically lack metallic properties. They can exist in different physical states, including gases (such as oxygen and chlorine), solids (such as sulfur), and liquids (such as bromine). Non-metals generally have lower melting and boiling points compared to metals and are poor conductors of heat and electricity.

Examples of non-metals include chlorine, oxygen, sulfur, fluorine, hydrogen, carbon, nitrogen, and phosphorus. Oxygen is essential for supporting combustion and is a vital component of the Earth’s atmosphere. Chlorine is widely used as a disinfectant, while fluorine is known for its reactivity and use in fluoridation of water. Carbon is a key element in organic chemistry and forms the basis of all known life forms.

In addition to metals and non-metals, there is a third category known as metalloids or semi-metals. Metalloids possess some properties of both metals and non-metals. They exhibit characteristics of metals, such as being semi-conductors of electricity, but also display non-metallic properties, such as brittleness. Metalloids are found along the “staircase” line on the periodic table, separating the metals from the non-metals.

Silicon and germanium are prominent examples of metalloids. They are used extensively in the semiconductor industry for manufacturing electronic devices. Metalloids find applications in areas that require a combination of metallic and non-metallic properties, such as in the production of transistors, solar cells, and fiber optics.

The classification of elements into metals, non-metals, and metalloids provides a useful framework for understanding their properties and behavior, allowing scientists and researchers to predict and manipulate their interactions in various chemical and physical processes.


The differences between metals and non-metals can be summarized as follows:

– State: Metals are generally solids at room temperature, except for mercury, which is a liquid. They have a metallic luster.
– Conductivity: Metals are excellent conductors of heat and electricity. They have a high thermal and electrical conductivity, allowing them to transfer heat and carry electrical currents efficiently.
– Malleability: Metals can be hammered or rolled into thin sheets without breaking. They are malleable and can undergo plastic deformation.
– Ductility: Metals can be drawn into wires without breaking. They are ductile and can be stretched into thin, elongated shapes.
– Shiny appearance: Metals have a shiny, reflective surface known as metallic luster.
– Density: Metals are often very dense, meaning they have a high mass per unit volume. This high density is due to the close packing of metal atoms in their structures.

– State: Non-metals can exist as solids, liquids, or gases at room temperature. For example, oxygen and chlorine are gases, sulfur is a solid, and bromine is a liquid.
– Conductivity: Non-metals are generally poor conductors of heat and electricity. They have low thermal and electrical conductivity. However, there are exceptions such as graphite, which is a form of carbon and can conduct electricity due to its unique structure.
– Brittleness: Non-metals tend to be brittle and break or shatter when subjected to stress. They lack the ability to undergo plastic deformation.
– Ductility: Non-metals are not ductile, meaning they cannot be stretched into wires without breaking. They do not exhibit the same level of flexibility as metals.
– Shiny appearance: Non-metals do not have the characteristic metallic luster and generally have a dull or non-reflective surface.
– Density: Non-metals usually have lower densities compared to metals, meaning they have a lower mass per unit volume. This lower density is due to the arrangement of atoms in their structures, which are typically less closely packed.

These differences in properties between metals and non-metals arise due to variations in atomic structure, bonding, and the arrangement of electrons within their atoms. These contrasting characteristics have significant implications for the applications and uses of metals and non-metals in various fields such as construction, electronics, and chemistry.


Valency is a crucial concept in chemistry that describes the combining power or capacity of an element. It indicates the number of electrons an atom of an element can gain, lose, or share when it forms chemical bonds with other atoms. Valency determines the type and number of bonds an element can form and plays a significant role in predicting the chemical behavior and reactivity of elements.

The valency of an element is often related to the number of electrons in its outermost energy level, also known as the valence shell. The valence electrons are the electrons involved in chemical bonding and are responsible for the element’s interactions with other atoms. Elements strive to achieve a stable electron configuration, commonly the “octet rule,” which involves having eight electrons in their valence shell. However, there are exceptions for elements with fewer or more than eight valence electrons.

Elements with complete valence shells, such as noble gases (helium, neon, argon, etc.), have stable configurations and tend to be chemically inert due to their full valence shells. They have a valency of zero since they neither gain nor lose electrons during bonding.

The valency of other elements is determined by the number of electrons needed to attain a stable configuration. For elements that have less than four valence electrons, tend to lose these electrons and have a positive valency equal to the number of electrons lost. For example, sodium (Na) has one valence electron in its outer shell and readily loses it to achieve a stable configuration, resulting in a valency of +1.

Elements that have four or more valence electrons tend to gain electrons to achieve a stable electron configuration. The valency of these elements is equal to the number of electrons needed to fill their valence shell. For instance, oxygen (O) has six valence electrons and requires two more electrons to attain a stable configuration. Therefore, oxygen has a valency of -2 since it tends to gain two electrons during bonding.

It is important to note that elements can have variable valencies depending on the compounds they form. Transition metals, for example, exhibit multiple valencies due to the availability of different energy levels for electrons to occupy. These elements can form compounds with different oxidation states or charges.

Valency is a crucial concept for understanding chemical bonding, the formation of compounds, and the prediction of chemical reactions. It provides insights into the behavior of elements and their tendency to gain, lose, or share electrons, ultimately influencing the formation of stable chemical structures.

Below are the valencies of some elements:

Element                                  Symbol                                   Valency

Aluminium                                Al                                             +3

Argon                                       Ar                                             Nil

Calcium                                    Ca                                            +2

Chlorine                                   Cl                                             -1

Sulphur                                      S                                    -2, -4 or -6

Sodium                                      Na                                           +1

Magnesium                               Mg                                           +2

Copper                                     Cu                                            +1 or +2

Carbon                                     C                                              -2 or -4

Barium                                     Ba                                            +2

Silver                                        Ag                                            +1

Iron                                          Fe                                             +2 or +3

Valencies have either positive or negative values showing whether electrons are gained or lost. If an element gains electrons, its value is negative but positive when it loses electrons.

Generally, metals exhibit positive valencies while non–metals tend to have negative valencies. Some elements exhibit more than one valency. Valency can also be called oxidation number or state.


A radical is a group of atoms that behaves as a single unit and carries either a positive or negative charge. These charged groups of atoms maintain their identity during chemical reactions and exhibit unique properties. In the case of negative-charged radicals, they are often referred to as anions.

An acid radical specifically refers to a small group of atoms carrying a negative charge that has acidic properties. These acid radicals are typically involved in acid-base reactions, where they combine with positively charged species called bases to form salts.

Let’s consider some examples of acid radicals:

1. Sulfate ion (SO₄²⁻): The sulfate ion is a polyatomic anion consisting of one sulfur atom bonded to four oxygen atoms. It carries a net charge of -2. The sulfate ion is a common acid radical found in various salts and acids, such as sodium sulfate (Na₂SO₄) and sulfuric acid (H₂SO₄). It plays a crucial role in many chemical processes and is involved in the formation of minerals and compounds in both natural and industrial settings.

2. Carbonate ion (CO₃²⁻): The carbonate ion consists of one carbon atom bonded to three oxygen atoms and carries a -2 charge. It is an acid radical found in compounds like sodium carbonate (Na₂CO₃) and calcium carbonate (CaCO₃), which is the main component of limestone and marble. Carbonate ions are also involved in biological processes, such as the carbonic acid-bicarbonate buffer system in the blood.

3. Nitrate ion (NO₃⁻): The nitrate ion consists of one nitrogen atom bonded to three oxygen atoms and carries a -1 charge. It is a common acid radical found in compounds such as potassium nitrate (KNO₃) and nitric acid (HNO₃). Nitrate ions are significant in the nitrogen cycle and serve as a nutrient for plants.

These acid radicals, along with others such as phosphate (PO₄³⁻), cyanide (CN⁻), and hydroxide (OH⁻), play essential roles in chemical reactions and have diverse applications in various industries and scientific fields.

Understanding acid radicals and their behavior is crucial for predicting the reactivity and properties of compounds. They contribute to the formation of salts, influence the pH of solutions, and participate in numerous chemical reactions. The presence and behavior of acid radicals significantly impact the chemistry of acids and the formation of acid-base pairs, providing a foundation for understanding the broader concepts of chemical reactions and the properties of compounds.

The valency of a radical corresponds to the charge it carries.

Radical                                     Formula                                    Valency

Ammonium                                          NH4+                                        +1

Hydroxide                                            0H                                           -1

Trioxonitrate(V)                                   N03                                          -1

Dioxonitrate(III)                                  N02                                          -1

Trioxocarbonate(IV)                           C032-                                            -2

Tetraoxosulphate(VI)                    S042-                                              -2

Hydrogen trioxocarbonate                 HC03                                          -1

Read also:

Structure of The Atom

Atomic Number, Relative Atomic Masses, Isotopes & Calculations

IUPAC Nomenclature of Chemical Compounds



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