Every single thing around us is made up of atoms and this atom , in turn, is made up of protons, neutrons and electrons. These atoms combine in various ways to form elements and molecules.
The scientists figured this much out a long while ago . Now, being terribly bored, they wanted to know why the atoms combined in the way they did and how electron lose and gain effects the compound or molecule
< I absolutely blame the netflix owner for not inventing netflix sooner for the past scientists, would have saved the current students from so much misery>
This gave birth to the new concept of Reduction and oxidation ( which is referred to as redox)
< DISCLAIMER -- This particular blog page consists of only a gist of all the major topics in this chapter including few important points, I have tried my best to elaborate on the major concepts but still would highly suggest you to read the NCERT textbook for complete understanding of this blog. >
Now, let's start
(I) What is OXIDATION NUMBER?
It is real or imaginary charge present on an atom, when it is present in combined form
Rules to find oxidation number
1) The sum of oxidation number of all atoms in the molecule or ions is equal to charge on the molecule or ion
2) Oxidation number of an element in uncombined form is zero
3) Alkali metals in compound have +1 oxidation number
4) Alkaline Earth Metals --> +2
5) Aluminium --> +3
6) Fluorine --> -1
7) Hydrogen --> +1
(Exception of metal hydrides , here, Hydrogen has -1 oxidation number)
8) Oxygen
Most of the cases --> -2
Peroxide bonding --> -1
Superoxide bonding --> -1/2
With fluorine ( OF2 and O2F2) --> +1
9) Amalgams --> 0 ( there is no bond formation taking place)
10) For all other elements, the oxidation number can vary from [ n to n-8] where n represents the group number
11) Highest oxidation number is possible is +8 shown by RuO4 , OsO4, XeO4
(II) Few Mixed Oxides reaction you should definitely remember
( You can find the oxidation numbers in the respective compounds after this)
(III) Important ( Let's be honest, completely bizarre) structures of compounds along with the oxidation number of central atom
(IV) Some Definitions
1. OXIDATION :-
*Addition of oxygen
* Removal of hydrogen
*Loss of electrons
*Increase in oxidation number
2. REDUCTION :-
* Removal of Oxygen
* Addition of Hydrogen
* Gain of electrons
* Decrease in oxidation number
3. REDOX REACTIONS
*These are the reactions in which oxidation and reduction takes place
4.OXIDISING AGENT
* A substance which will oxidise another chemical
* It gets reduced
Identification -- It is the compound in which element is present in highest oxidation state
5. REDUCING AGENT
* A substance which will reduce another chemical
* It gets oxidised
Identification -- It is the compound in which element is present in lowest oxidation state
6. DISPROPORTIONATION REACTION
* These are the ractions in which same element undergoes both oxidation and reduction
Example :-
7. COMPROPORTIONALISM
*Reverse of Disproportionalism
(V) Balancing reactions
Method.1 -- Oxidation number method
Step.1 -- Find the charge per molecule using oxidation number
Step.2 -- Equalise the charges
Step.3 -- Balance atoms undergoing change
Step.4 -- Balance charges ( by adding either H+ or OH- depending on the medium)
Step.5 -- Balance 'O' by adding H2O
Method.2 -- Half reaction method
Step.1 -- Identify oxidation and reduction reaction
Step.2 -- Split the reaction into oxidation half reaction and Reduction half reaction
Step.3 -- Balance all atoms other than 'O' and 'H'
Step.4 -- Balance 'O' atoms by adding H20 on deficient side
Step.5 -- Balance 'H' by adding H+ on deficient side
Step.6 -- Balance charge by adding electrons
Step.7 -- Equalise electron on both sides ( Multiply with suitable number to make electrons same)
Step.8 -- Add both equation!
That covers up the basic of redox folks! I will be covering the other topics under this chapter in a different blog so keep your eyes peeled!
and following the traditions, here is a chemistry joke/meme
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