Elements
Element:-The substance made up of same type of atoms, having same atomic number (same number of electrons and protons) and cannot be decompose into simple substances by ordinary chemical means, is known as element.
Same type of atoms, jin ka atomic number same ho (jin k nucleus me protons ki tadad same ho) mil kr element bnate hn, jise simple chemical process se decompose nhi kiya ja skta.
In the early ages only nine elements were known.These elements were named as gold, carbon, tin, mercury, silver, lead, copper, sulphur and iron.Now a days, there are 118 known elements from which 92 are naturally occurring elements.
Starting me sirf 9 element k bare me duniya janti thi. Jin k nam gold, carbon, tin, mercury, silver, lead, copper, sulphur or iron hn. Lakin aj k dor me 118 elements k bare me duniya jan chuki ha or in 118 elements me se 92 elements aase hn jo k kudarti tor pr duniya me majood hn or baki ko insano ne kdh bnaya ha.
Elements are basically the smallest particles of a compound. So, it means that elements can not b further subdivided. As we know that elements are made up of same type of atoms, it means that the atoms of an element have same number of electrons and protons in them.
Some naturally occurring elements which are present in our surrounding are as follows and their weight by percentage is also shown.
Atmosphere:-
Nitrogen. 78%Oxygen. 47%
Oxygen. 86%
Earth crust
Oxygen. 21%
Silicon. 28%
Hydrogen. 11%
Ocean:-
Argon. 0.9%
Aluminum. 7.8%
Chlorine. 1.8%
Elements may be solid, liquid and gas. Majority of them are solids like gold, copper, silver and zinc, iron etc.A few of them are liquid and a very few are gas.
Elements matter ki teno states me pae jate hn. Mtlb, elements solid b hote hn, liquid b or gass b. Zyada tr elements solid form me majood hn maslan gold, copper, silver, zinc or iron. Baki kuch elements liquid form me or bht hi km elements aase hn jo k gas ki form me majood hn.
But if we want to divided elements on the basis of properties, then the elements may be divided into three categories, Metals, Non-metals and Metalloids. And here you have to know that from all these elements 80% of elements are metals.
Agr hm elements ki basic properties ko dekhte huae elements ko different categories me divided krna chahen to elements ko hm 3 categories me divided kr skte hn. Metals, Non-metals and Metalloids. 80% elements, metals ki halat me milte hn or baki k 20% non-metals or metalloids hn.
Symbols:-
Symbols are abbreviations for the name of elements.
As you know that elements are represented by symbols. The symbols can be taken from the name of the elements.First word of the name of element will be its symbol and if there are two or more elements having same first words, then the second word will use with that.
For Example :- "H" is the symbol of hydrogen, "He" is the symbol of helium, "O" is the symbol of oxygen, "Cl" is the symbol of chlorine.
Elements ko symbols k zreay likha jata ha. Symbol, element k nam ka first letter hota ha. Or agr 2 ya 2 se zyada elements k nam ka first letter same ho to first letter k sath second letter likh k us element ka symbol bnaya jata ha
For Example:- Hydrogen ka symbol ha "H" or Helium ka symbol ha "He".
Valency:-
It is the combining capacity of an element with other elements.
The combining capacity of an element with other elements is known as its valency. The valency of an element is depends upon the number of electrons present in its outermost shell.The number of electrons present in the outermost shell of an electron is equal to the number of elements with which it combines.It means that if any element has one electron in its outermost shell it means that it can combine with only one any other element, and if the element have 2 electrons in its outermost shell so, it will combine with two other elements. The valency of some elements also depends upon the number of electrons to complete their outermost shell. If any elements needs 1 electron to complete its outermost shell then its valency will be one.
For Example :- The valency of hydrogen (H) and chlorine (Cl) is 1 because hydrogen has 1 electron in its outermost shell and chlorine needs 1 electron to complete its outermost shell.
1 element mazeed kitne elements k sath jur skta ha isy us element i valency ya phir combining capacity bolte hn. kisi b element ki valency is bat pr depend rti ha k us element k sb se bahir wale shell me kitne electrons majood hn. Valency outermost shell me majood electrons k number pr depend krti ha iska mtlb ye ha k valency element k stability pr depend krti ha. Agr 1 element k outermost shell me sirf 1 electron ha to wo us electron ko donate kr de ga or 1 bond bnay ga or isi trha agr kisi element ko apne outermost shell ko complete krne k liay 1 electron ki zaroort ha to wo kisi or element se 1 electron le kr us element k sath jur jy ga.
For Example:- Hydrogen ki valancy 1 ha kun k is k outermost shell me sirf 1 electron majood ha jise kisi or element ko donate kr k us k sath bond bna le ga. Isi trha Chlorine ki valency b 1 lakin is k outermost shell me 7 electrons hote hn to isy stable hone k liay 1 electron ki zaroort ha jo k ye kisi dusre element se le k us k sath bond bna leta ha is liay iski valency b 1 ha.
There some elements are also present who have more then one valency. e.g, Iron (Fe) have two valencies 2 and 3. So, How we will distinguish them? The element with lower number of valency will have some modification in its name that , its name will end will 'ous' and the element with higher valency will end will 'ic'. So, the name of "Farrum or Iron" with low valency will be "Farrous" and with higher valency is "Farric".
Kuch elements aase b hn jin ki 2 valencies hn. In elements ki alg phchan k liay km valency wale element k nam k akhir pr 'ous' lgate hn or zyada valency wale element k nam k akhir pr 'ic' lgate hn.
For Example:- Ferrum (Iron) ki 2 valencies hn, 2 or 3. jis ki valency 2 ho uska nam 'Farrous' bolen ge or jiski valency 3 hogi uska nam 'Farric' hoga.
Written By:- M.Ashir Azeem
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