How to differentiate elements as metals and non metals by looking at their valencies?
- Valence shell is the outermost shell of an atom.
- The electrons present between the valence shell are known as valence electrons.
- Each & every element always try to become happy by completing its own Octet ie. by keeping 8 electrons in its valence shell.
- There are some elements who become happy by stealing the electrons of the other elements. Such thieves elements are called Non-Metals.
- Other innocent elements whose electron get stolen are called Metals.
-
Lets take the favourite example of students ie. formation of NaCl
The Electronic configuration of Sodium (Na) is,
- K=2 , L=8, M = 1
or - 1s2,2s2,2p6,3s1
-
While the Chlorine ( Cl ) have Electronic configuration,
- K=2, L=8, M= 7
or -
1s2,2s2,2p6,3s2,3p5
-
Each & Every element always try to complete its octet by keeping 8 electrons in its valence shell.
-
Sodium hates it own electron from its valence shell because there is only one electron in its valence shell (K=1). Sodium has already completed the octet in previous inner shell of valence shell (L=8). That is why Sodium don't want that 1 one electron situated in valence shell. Sodium is sad now. :(
-
On the other hand, Chlorine ( Cl ) has 7 electron in its valence shell so Chlorine (Cl) want only one Electron in its valence shell to become happy by completing its octet. Hence due to lack of 1 electron Chlorine is also upset. :(
-
That is why Chlorine steals that unwanted electron which was present in valence shell of Na.
-
Now, Outermost shell of Na ie. shell-M disappears because there is no any Electron. It leads to the Inner previous shell-L to be the outermost shell of Na. ie. Valence shell of Na which contains already 8 Electrons. So Now Na is happy! :)
-
Initially Chlorine had 7 electrons in its valence shell, Just now, Chlorine have stolen that 1 unwanted electron of sodium. So now Cl has 7+1=8 Electrons in its valence shell. It means octet is completed. So Cl is also happy now ! :)
-
Sodium (Na) lost its 1 electron, it means Na lost its 1 -ve charge ie. Na got 1 +ve charge. Hence Sodium (Na) become Cation.
-
Chlorine (Cl) steals the electron & hence it got 1 -ve charge ie. Chlorine (Cl) become Anion.
-
Both Na & Cl made happy each other, Na has 1 +ve charge while the Cl have 1 -ve charge. Since Equal & Opposite charges attract each other. So Sodium (Na) & Chlorine (Cl) Sticks together & forms NaCl, Because both made happy each other ! :)
-
Your question asks, "How to know the element whether it is metal or non-metal by using number of valence shell electron?" Right?
That is why I've given you this funny example, by using this example you can conclude that,
- Non-Metal :- The element who becomes happy (completes its octet) by stealing the electrons of other element. eg. Mostly gases like Chlorine.
- Metal :- That innocent element who becomes happy when its electrons got stolen. eg. Na
- Valence shell is the outermost shell of an atom.
- The electrons present between the valence shell are known as valence electrons.
- Each & every element always try to become happy by completing its own Octet ie. by keeping 8 electrons in its valence shell.
- There are some elements who become happy by stealing the electrons of the other elements. Such thieves elements are called Non-Metals.
- Other innocent elements whose electron get stolen are called Metals.
-
Lets take the favourite example of students ie. formation of NaCl
The Electronic configuration of Sodium (Na) is, - K=2 , L=8, M = 1
or - 1s2,2s2,2p6,3s1
-
While the Chlorine ( Cl ) have Electronic configuration,
- K=2, L=8, M= 7
or -
1s2,2s2,2p6,3s2,3p5
-
Each & Every element always try to complete its octet by keeping 8 electrons in its valence shell.
-
Sodium hates it own electron from its valence shell because there is only one electron in its valence shell (K=1). Sodium has already completed the octet in previous inner shell of valence shell (L=8). That is why Sodium don't want that 1 one electron situated in valence shell. Sodium is sad now. :(
-
On the other hand, Chlorine ( Cl ) has 7 electron in its valence shell so Chlorine (Cl) want only one Electron in its valence shell to become happy by completing its octet. Hence due to lack of 1 electron Chlorine is also upset. :(
-
That is why Chlorine steals that unwanted electron which was present in valence shell of Na.
-
Now, Outermost shell of Na ie. shell-M disappears because there is no any Electron. It leads to the Inner previous shell-L to be the outermost shell of Na. ie. Valence shell of Na which contains already 8 Electrons. So Now Na is happy! :)
-
Initially Chlorine had 7 electrons in its valence shell, Just now, Chlorine have stolen that 1 unwanted electron of sodium. So now Cl has 7+1=8 Electrons in its valence shell. It means octet is completed. So Cl is also happy now ! :)
-
Sodium (Na) lost its 1 electron, it means Na lost its 1 -ve charge ie. Na got 1 +ve charge. Hence Sodium (Na) become Cation.
-
Chlorine (Cl) steals the electron & hence it got 1 -ve charge ie. Chlorine (Cl) become Anion.
-
Both Na & Cl made happy each other, Na has 1 +ve charge while the Cl have 1 -ve charge. Since Equal & Opposite charges attract each other. So Sodium (Na) & Chlorine (Cl) Sticks together & forms NaCl, Because both made happy each other ! :)
-
Your question asks, "How to know the element whether it is metal or non-metal by using number of valence shell electron?" Right?
That is why I've given you this funny example, by using this example you can conclude that, - Non-Metal :- The element who becomes happy (completes its octet) by stealing the electrons of other element. eg. Mostly gases like Chlorine.
- Metal :- That innocent element who becomes happy when its electrons got stolen. eg. Na
