Periodic Table

Question 1

elements in the same period

Answer 1

same number of electronic shells

Question 2

elements in the same group

Answer 2

same outer electronic configuration, so same number of valence electrons

Question 3

what is the relationship between max oxidation number and valence electrons

Answer 3

maximum attainable oxidation number is equal to the number of valence electrons of an atom of the element, if all the valence electrons are involved in bonding

Question 4

how is the relationship between max oxidation number and valence electrons attainable

Answer 4

period 3 elements have unoccupied low lying 3d orbitals which allow octet structure to be expanded and valence shell can have more than 8 electrons

Question 5

explain boiling point of alcl3

Answer 5

exists as dimers of al2cl6
has larger electron cloud, higher ease of polarisability, stronger id-id, more energy needed to overcome the id-id
higher boiling point than other covalent chlorides, bit lower than ionic chlorides

Question 6

how does hydrolysis occur

Answer 6

cations with high charge density and high polarising power are able to distort electron cloud of water molecule and weaken O-H bond
in presence of water, O-H bond undergoes heterolytic fission readily to release H+

Question 7

how does extent of hydrolysis affect solution

Answer 7

greater the charge density of cation, the greater the extent of hydrolysis, more H+ released, lower the pH of the solution

Question 8

why can sicl4 undergo hydrolysis

Answer 8

1. si atom is large and there will be less steric hindrance around Si atom for nucleophilic water to attack
2. Si has empty low lying 3d orbitals to accept the lone pair of electrons from water

Question 9

why is ccl4 inert to water

Answer 9

1. attached to 4 large chlorine attoms which hinder approach of h2o nucleophile
2. carbon has no low lying empty orbitals to accept lone pair of electrons from water