(a) Give three points of difference between lanthanoids and actinoids.

(b) Give reason and select on one atom/ion which will exhibit asked property:
(i) `Sc^(3+)` or `Cr^(3+)` (exhibit diamagnetic behaviour)
(ii) Cr or Cu (high melting and boiling point)

(a) Give two differences between Lanthanoids and Actinoids. (b) How many unpaired electrons are present in Fe^(3+) and Zn^(2+) (c) Why is La(OH)_3 stronger base while Lu(OH)_3 is weaker base?

(i)with reference to structural variability and chemical reactivity write the differences between lanthanoids and actinoids (ii) Mame a member of the lanthanoid series which is well known to exhibit +4 oxidation state (iii) Complete the following equation : MnO_(4)^(-)+8H^(+)+5e^(-)rarr (iv) out of Mn^(3+) and Cr^(3+) which is ore paramagnetic and why? Atomic nos : Mn =25 Cr =24

(a) What is meant by positive tropism and negative tropism? Explain with examples. (b) Define thigmotropism. Give one example of thigmotropism. (c) What is the difference between thigmotropism and thigmonasty? Name one plant which exhibits thigmotropism and one plant which exhibits thigmonasty. What behaviour (or responses) of these plants make you think that they exhibit thigmotropism and thigmonasty respectively?

(a)Give one point of difference betweeen an atoms and an ion. (b)Give one example of each of polyatomic cation and a polyatomic anion. (c )Identify the correct name of FeSO_(3) from the given names-Ferrous sulphate, Ferrous sulphide, Ferrous sulphite. (d)Write the chemical formulae for the chloride the magnesium.

Describe giving reason which one of the following pairs has the property indicated? (a). Fe or Cu has higher melting point. (b). Co^(2+) or Ni^(2+) has lower magnetic moment.

Explain giving reason: (i) Treansition metals and their compounds generally exhibit a paramagnetic behave . (ii) The chemistry of actinoids is not so smooth as that of lanthanoids.

(a) Complete the following chemical equations for reactions : (i) MnO_(4(aq))^(-) + S_(2)O_(3(aq))^(2-) + H_(2)O_((l)) to (ii) Cr_(2)O_(7 (aq))^(2-) + H_(2)S_((g)) + H_((aq))^(+) to (b) Give an explanation for each of the following observations : (i) The gradual decrease in size (actinoid contraction) from element to element is greater among the actinoids than that among the lanthanoids (lanthanoid contraction.) (ii) The greatest number of oxidation states are exhibited by the members in the middle of a transition series. (iii) With the same d-orbitals configuration (d^(4)) Cr^(2+) ion is a reducing agent but Mn^(3+) ion is an oxidising agent .