Draw the structure of carbonyl group and indicates clearly
(i) hydridised state of carbon
(ii) the `sigma` and `pi` bonds present
(iii) electrolphilic and nuclophic centres in it.

The number of sigma and pi -bonds present between the two carbon atoms in calcium carbide are respectively-

(1) How many sigma and pi bonds are present in (i) CH_(2) = CH - CN and (ii) CH_(2) = C CHCH_(3) ?

For crystal sodium chloride, state (i) the type of lattice in which it crystallises. (ii) co-ordination number of each sodium ion and chloride ion in the crystal lattice. (iii) number of sodium and chloride ions present in a unit cell of sodium chloride. (iv) the structural arrangement of sodium chloride crystals.

Predict the hybridisation of each carbon in the molecule of organic compound given below. Also indicate the total number of sigma and pi bonds in this molecule.

Read the following statements and select the correct option (i) Blood cells secrete fibres of structural proteins called collagen and elastin (ii) Neuroglial cells protect and support the nephrons (iii) Osteocytes are present in spaces called lacunae (iv) Striated muscle fibres are bundled together in a parallel fashion (v) Biceps are involuntary and striated.

Draw the structure of the following : (i) 3-Methylbutanal , (ii) p-Methoxybenzaldehyde , (iii) 4-Chloropentan-2-one (iv) p,p-Dihydroxybenzophenone, (v) p-Nitropropiophenone , (vi) 4-Methylpent-3-en-2-one,

Account for the following. (i) +3 oxidation state of lanthanides is the most stable. (ii) A few 4f elements show +2 or +4 oxidation states in addition to the characteristic oxidation state of +3. (iii) Lanthanides are grouped together.