Question

Please teach me how to calculate oxidation no ,coordination no and effective atomic no. For Jee main please please

Answer 1

Heya.......!!!


♠ HOW TO CALCULATE OXIDATION No. :

➡ first of all learn the oxidation number of some common elements like oxygen ,hydrogen ,aluminium,etc......

➡ For monoatomic ions, the oxidation state is given by the charge on the ion.
e.g. Cl- (-1), Fe2+ (+2), Fe3+ (+3), S2- (-2), Ca2+ (+2), H+ (+1) etc

➡ The sum of the oxidation states in a molecule is zero.
e.g. CH2O » (0) + 2(+1) + (-2) = 0
CH3OH » (+2) + 3(+1) + (-2) + (+1) = 0 .

➡ Certain elements when present in compounds have common oxidation states.
a) alkali metals (Li+ , Na+ , K+ ) are always +1
b) alkali earth metals (Mg2+, Ca2+, Sr2+, Ba2+) are always +2
c) hydrogen is +1 (except in metal hydride compounds such as LiH)
d) oxygen is -2 (except in peroxides such as H2O2)
e) halogens (F- , Cl- , Br- , I- are usually -1 ).



♠ HOW TO CALCULATE COORDINATION No.:

➡ Coordination number is often 2 x oxidation number (many exceptions)
• Mostly predictable geometry:
» Coordination number = 2, linear
» Coordination number = 4, square planar or tetrahedral
» Coordination number = 6, octahedral
Ligan .

➡ In the case of non-metal compounds, the situation is much more Easy . Just learn number of oxidation states( OS ) of the s- and p-block elements and the coordination number around any given atom can be predicted by filling the shells .

➡ For molecules and polyatomic ions the coordination number of an atom can be taken out by counting the other atoms to which it is bonded .



♠ HOW TO CALCULATE EFFECTIVE atomic number .

➡ Atomic number of d metal atom-oxidation state+2×coordination number .

➡ effective atomic number is numerically equal to the atomic number of the noble-gas element found in the same period in which the metal is situated.

➡ the effective atomic number of the cobalt atom in the complex [Co(NH3)6]3+ is 36.
➡ The EAN rule is often referred to as the “18-electron rule”.


HOPE IT HELPS U ☺