118 Elements and Their Symbols and Atomic Numbers-Class 11 Chemistry Notes

Everything in the universe is composed of basic elements, and at their smallest level, these elements are atoms.

There are a total of 118 elements in the modern periodic table out of which 98 are found in nature rest are chemically synthesized in laboratories. An atom of any element is composed of electrons, protons, and neutrons and possesses a different property from the other.

118 Elements and their Symbols and Atomic Numbers

The Tabulated view of all 118 elements and their symbols along with their atomic number, element name, atomic mass, and number of protons and neutrons is described below:

What is a Periodic Table?

Initially, the number of elements was small, and the knowledge of the physical and chemical properties of these elements was also limited, but in the early 19th century the discovery of new elements and growth in the knowledge of physical and chemical properties of elements had become hard for the scholars to remember the behavior and properties of all the elements.

Thus a need for a systematic arrangement of elements was there, where the elements are stacked based on their properties, physical properties such as melting point, boiling point, and chemical properties such as electronegativity, valence electron, etc and thereafter the periodic table was introduced.

A periodic table is a tabular arrangement of chemical elements in the increasing order of the atomic number which is the number of protons in their nucleus. The arrangement of the elements thus formed shows a recurring pattern in their properties known as “periodic laws”.

118 Elements in Periodic Table

Following illustration represents all 118 elements in periodic table:

Atomic Number

The nucleus of each element consists of a different number of protons and neutrons, the number of protons in each nucleus of each element is found to be unique, so it became the base for arranging the elements in increasing order of their nucleus protons. Number of protons in the nucleus also determines the electronegativity and other factors of the elements.

The number of protons in the nucleus of each element is unique and it is referred as Atomic Number. It is the fundamental property of any element and is denoted by the symbol “Z”.

The elements in the periodic table are arranged in the increasing order of their atomic number, for example, H (Hydrogen) has atomic number 1, He (Helium) has atomic number 2, and so on.

Mass Number

The individual mass of an atom of an element is very minute and also difficult to measure. The mass of an electron is approximately 9.10938356 × 10^-28 g, the mass of the proton is 1.6726219 × 10^-24 g and the mass of neutron is 1.675 × 10^-24 g. Since the mass of an atom is merely and remembering the exact mass was a tough job, so the mass number was introduced which is the total number of protons and neutrons in its nucleus.

The Mass Number of an atom is the total number of protons and neutrons in its nucleus. It is represented by the letter A. The mass number of an atom of an element gives an approximate measure of the total mass of the atom. It is expressed in atomic mass units (u) or unified atomic mass units (AMU).

Where 1 AMU = 1.67377 × 10 ^-24 g

Symbols Of Elements

Each element is assigned some unique symbol which is usually an English letter (or two). These symbols are used universally to represent and uniquely identify that particular element and are also used for scientific purposes to represents elements in a clean and concise manner. Thus we can say that,

Symbols of element are shorthand to uniquely identify and represent that element.

The symbols of the elements are widely used to represent the elements in chemical formulas, equations, and other representations of chemical reactions.

How Symbols are Derived?

The symbols of elements are derived from the name of the element in English or another language eg. the symbol of Hydrogen is H, that comes from its name in English. It is important to note that the symbol of an element is usually a capital letter and when it contains two letters, the second letter is smaller letter. However, in cases where the first two letters are already taken, or for historical reasons, the symbol may not directly correspond to the element’s name (e.g., Fe for iron comes from its Latin word “ferrum”).

118 Elements and Their Symbols: FAQs

1: Who is the Father of the Periodic Table?

Mendeleev is often credited as the father of periodic table.

2: What is an Element?

An element is a substance that consists of only one type of atom, and each element is characterized by the number of protons found in the nucleus of its atoms.

3: What is an Atom?

An atom is the basic building block of matter and it is made up of protons, neutrons, and electrons. An atom is the smallest unit of an element that is responsible for the chemical properties of that element.

4: What are Chemical Symbols and their Significance?

Chemical symbols are shorthand representations of an element. These symbols consist of one or two letters often derived from the name of the element. They have a significant role in communicating information about elements in a concise and standardized manner.

5. What has only 1 atom?

Some elements consist of only 1 atom and they are known as monoatomic. For example, Helium, and Potassium

6: What are Isotopes of Hydrogen?

Hydrogen has three isotopes namely Protium (H¹₁ ), Deuterium(H¹₂), and, Tritium(H¹₁).

7: What is the Connection between the Atomic Number and the Number of Protons?

The atomic number of an element is equal to the number of protons in the atom of the element.

8: Which is the most Reactive Metal?

Francium(Fr) is considered the most reactive metal of all.

9: Which Metal Remains Liquid at Room Temperature?

Mercury is the only metal which remains in a liquid state at room temperature.