Thursday, October 13, 2022
11:40 AM
The trend / common q
Explanation
Down group 2 carbonates why
longer time needed for white ppt
form oxide
Thermal stability increases
Ionic radius increase
Charge density decrease
Polarizing power decrease
Less distortion of anion electron cloud
Higher temp required for thermal decomposition
Why 1st n 2nd ionization energy
of transition metals ( dblock) the
same
Involve the removal of 4s eAcross the period proton no increase and nuclear charge increase
Since more e- added to 3d (which is inner shell) the shielding effect increase
Small increase in IE
Melting point (ref to the bonds
like ionic and id-id etc)
Has strong electrostatic attraction between ion ( ionic bond is stronger than
id-id etc)
Simple covalent molecule w weak intermolecule forces such as idid n
hydrogen bond which is weaker than ionic
# covalent is very strong but btwn molecule is the forces u break to melt
HI>HBr>HCl as HI has higher no of e-, stronger id-id, more energy required to
over come the force of attraction ( also for halogens )
HF Don’t follow cz its hydrogen bond
Thermal stability ( refer to bond
strength and bond length )
HI<HBr<HCl down the grp thermal stability decreases, size of atom increase,
longer bond length, lower bond energy so easily decompose
Why no dipole moment ?
Linear dipole moment cancel out so no net movement of e-
Why greater net dipole moment?
Larger electronegative difference
Why PCL5 exist but NCl5 cannot
form
PCL5 in period 3 has 3d orbital but N is in period 2 so cannot have more than
8e-
PCL5 vs PCL3 why PCL5 have
different m.p
Pcl5 have more eStronger id-id so need more energy to overcome
Reactivity
C-I more reactive than C-Cl, as has longer bond length lower bond energy so
less energy needed to break bond
Acid strength (how easily H+ released ) increases down the grp
Oxidizing power of halogens decreases down the group
F2 is the strongest as strong nuclear chare , low no of e- filled shells so strong
attraction ( less shielding effect)
Reducing power of halide ions decreases down the group
I- ion lose e- easily as weak nuclear charge, high shielding effect
Why not reliable using
substitution of halogenoalkane
frm alkane
Random and all c-h in alkane can be substituted
Multiple halogenated propane
Why enthalpy changes of
atomization is higher for bromine
than iodine than cl and f
Cl2 n F2 is gases
Br liquid n I is solid
Difference in sulfuric acid for Nacl Nacl : H2so4 acts as an acid ( don’t change oxidation state)
and Na I
NaI: H2SO4 acts as oxidising agent for I- to I2
I- stronger reducing agent than ClLattice energies w least
exothermic ( weakest ionic bond)
The one w the higher ion number like +2 > +1 will have stronger bond
Bigger size, less charge density so weaker
AS Page 1
Lewis acid - lone pair
reciever