118 elements and their symbols
118 elements and their symbols were discovered now.
When we study about elements we come to know that elements were discovered and arranged in the form of a table by Mendleeve.
He arranged the elements according to their increasing atomic masses. And this is the first attempt to arrange the elements.
Later on this attempt has been rejected and the elements again arranged by another scientists Mosely.
He arranged the elements according to increasing their atomic number. And now a days this arrangement is used.
The periodic table consist of 7periods and 18 groups.
Periods are the horizontal lines in the periodic table from left to right .
While groups are the vertical columns in the periodic table.
118 elements and their symbols
|Name of the Element||Symbol of the Element||Atomic Number|
Definition of elements
We can say that every thing around us is composed of elements. Our universe is also composed of many types of elements. Elements is simply defined as,
It is a substance that is made from same type of atoms, which have same atomic number and it cannot be broken down into simple substances with the help of chemical sources .
Oxygen, silver, hydrogen, nitrogen, argon etc.
An element is a substance formed by the same type of atoms. It cannot break down into another simpler substance. Everything in the universe contains atoms of one or more elements.
The number of electrons in the atom of a element can vary.
Early concept of Element
In the early ages, only nine elements were known as :
Carbon, Gold, silver, Tin, Mercury, Lead Copper, Iron and Sulphur.
In ancient time, it was considered that were the substance that could not be broken down into simpler units by ordinary chemical process. Until the end of nineteenth century sixty three elements had been discovered.
Now, 118 elements have been discovered, out of which 92 are naturally occurring elements.The discovery of elements is not over. And new elements are discovering with the passing days. And there is large space in periodic table to accommodate these new elements.
Properties of Elements
Some typical properties of elements are as follows :
1. Elements occur in nature in free and combined form.
2. Elements may be solids, liquids or gases.
3. Each element is made up of unique and pure type of atoms.
4. All atoms have very specific properties.
5. Elements cannot be broken down by various chemical means into two or more different simpler substances.
- Majority of elements exist in solid state e.g , sodium, copper, zinc and gold etc.
- There are few elements which occur in liquid state e.g mercury and bromine.
- A very few elements exist as gases e.g nitrogen, oxygen, chlorine and hydrogen.
6. All naturally occurring elements found in the world have different percentage in the Earth’s crust, oceans and atmosphere.
7. The elements are represented by “Symbols” which are abbreviation for the name of elements.
Note: (A symbol is taken from the name of that element in English, Latin, Greek or German)
In case of one letter symbol :
Symbol of hydrogen is “H” symbol of carbon is “C”
And In case of two letter symbol :
Symbol of calcium “Ca”
Symbol of sodium “Na”
8. The unique property of an element is “Valency” . It is combining capacity of an element with other elements. It depends on the number of electrons in the outermost shell.
Classification of elements
On the behalf of the properties we can divide the elements as :
- Non metals
An element which is good conductor of heat and electricity, malleable and ductile and has a shiny surface is called a metal.
Sodium, silver, Iron etc.
An element which is a bad conductor of heat and electricity and not malleable and not ductile and not shiny in nature is called a non-metal.
Hydrogen, chlorine (gas)
Carbon, sulphur (solid)
An element which have properties of both metals and non-metals is called a metalloid.
Antimony (Sb), Silicon (So), Boron (B).