Account for the following : (i) Alkali metals show only +1 oxidation state .
(ii) The hydroxides of alkali metals are strong bases .
(iii) Na and K impart colour to the flame but Mg does not .
(iv) Li is the best reducing agent in aqueous solution .

Give reasons for the following: a. Alkli metals do not occur free in nature. b. Alkali metal salts impart characteristic colour to the flame. c. Caesium is used in photoelectric cell. d. Alkali metals are good reducing agents in aqueous medium.

Assign reasons for the following (i) alkali metals impart characteristic colour to flame (ii) Alkali metals are strong reducing agents. (iii) An aqueous solution of Na_(2)CO_(3) is basic in nature.

a. Name the alkali metals which form superoxides on heating in excess of air. b. Name the alkali metal which floats on water without any apparent reaction with it. c. Name the main factor which is responsible for the anomalous behaviour of lithium. d. What is the general name for element of group 1 ? e. Give the name of the alkali metal which is radioactive. f. Name the alkali metal which shows diagonal relationship with magnesium. g. Name teh alkali metal which acts as the strongest reducing agent in aqueous solution.

Give reasons for the following: (i) Transition metals exhibit a wide range of oxidation states. (ii) Cobalt (II) is very stable in aqueous solutions but gets easily oxidised in the presence of strong ligands. (iii) Actinoids exhibit a greater range of oxidation states than lanthanoids.

(a) Account for the following : (i) Mn shows the highest oxidation state of +7 with oxygen but with fluorine it shows the highest oxidation state of +4. (ii) Cr^(2+) is a strong reducing agent. (iii) Cu^(2+) salts are coloured while Zn^(2+) salts are white. (b) Complete the following equations : (i) 2MnO_(2) + 4KOH + O_(2) overset(Delta)(to) (ii) Cr_(2)O_(7)^(2-) + 14H^(+)6I^(-) to

Choose the correct answers: a. Which of the following alkali metal is the most electropositive ? i. Na , ii. K , iii. Rb , iv. Cs b. Ehich of the following alkali metals has the lowest m.pt. ? i. Li , ii. K , iii. Na , iv. Rb c. Which of the following is the stronger reducing agent ? i. Li , ii. Na , iii. K , iv Rb

Assign reasons for the following : (i) Cu(I) ion is not known to exist in aqueous solutions. (ii) Transition metals are much harder than the alkali metals. (iii) From element to element actinoid contraction is greater than the lanthanoid contraction.