d & f block
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Why is ns^0-2 written in d orbital valence shell electronic config?
Since Pd has 0 e`s in S orbital
What are transition elements?
Those which have incompletely filled d-orbitals in ground and excited (oxidation) state
Why are Zn, Cd & Hg not transition metals?
They have completely filled d-orbitals even after losing e’s from s orbital
Zn & Hf occur together in nature. Why?
Due to same properties like atomic size
All groups have metal behavious except for
group 12
When no of unpaired e’s are more, bonding in metal
increases
Down the group, atomisation enthalpy
increases
what is enthalpy of atomization?
Energy needed to break the bond to atoms
Why does atomic size decrease and gradually increase again across the period?
Due to shielding effect, nucleus is not able ot hold all e’s
What is lanthanoid contraction?
gradual decrease in the atomic and ionic size of lanthanoids with an increase in atomic number
Why is lanthanoid contraction seen in 5d & 6s series & 4d and 5d series?
14 e’s offer poor shielding effect from the element Hf which causes decrease in atomic size
Why does density of 3d elements increase from Sc to Zn?
Atomic mass increases
Why is ionisation enthalpy for 3d series irregular?
Due to irregularity in atomic size, it is lower for Cr due to absence of change in config while Zn has change in 4s config. b
If reduction potential is high, its stabitlity is
less in aq solution
Why is Cu1+ less stable than Cu2+?
Cu1+ has greater reduction potential and Cu2+ is surrounded by many water molecules due to which hydration enthalpy increases so it is stable
What happens when Cu+ is present in aq. sol?
It undergoes oxidation & reduction at the same time called disproportionation rn.
Why does Cu have +ve potential?
2nd ionisation enthalpy is very high due to which sum of enthalpies is +ve
Why does Mn show a less tendency to get reduced?
After losing 2 e’s, it has stable half filled d orbital and -ve potential
If potential is +ve, it will show more tendency to
get reduced
Ni has -ve potential due to
high hydration enthalpy
why is there irregularity in potentials?
Due to irregularity in sublimation & ionisation enthalpies
The stability of divalent ions decrease. Why?
Since the potentials are becoming less -ve across the period.
Why is Mn2+ resistant to oxidation but Fe2+ is not?
Due to half filled orbitals in Mn2+
Why is reduction potential of Mn3+ high?
It is easy for Mn3+ to gain 1 e’ to be stable