An element occupies group No.14 and period number 2 exists in different allotropic forms. One form of this element has lubricating property (A). Another form is the hardest substance (B). New allotrope of this element is named as `Buckyball' (C) and it is superconducting. Identify the element, (A) (B) and (C).

An element occupies group no.13 and period number 2 is an representative element of that group reacts with carbondioxide and forms an oxide (A). (A) reacts with CuSO_(4) give blue beads (B). Identify the element compound (A) and (B). Write the reaction.

An element occupies group No.16 and period number 2. This element on passing through silence electric discharge forms (A). (A) also reacts with lead sulphide and forms (B). (A) also reacts with BaO_(2) and forms (C). It reacts with H_(2)O_(2) and forms (D). Identify the dement (A), (B), (C) and (D).

An element occupies group number 1 and period number 2. This element burns with air and forms compound A. With water, it gives compound B, with hydrogen it forms an ionic compound C. Identify the elements, A, B and C.

An element occupies group number 2 and period number 3. This element reacts with oxygen and nitrogen to form compound A and B. It is a strong electropositive metal so it displaces Ag from AgNO_3 solution. With concentrated nitric acid, it forms compound C. Identify the element, compound A, B and C.

An element A occupies group number 17 and period number 2, is the most electronegative element. Element A reacts with another element B, Which occupies group number 17 and period number 4, to give a compound C. CompoundC undergoes sp^3 d^2 hybridisation and has octahedral structure. Identify the elements A and B and the compound C. Write the reactions.

An element occupies group number 15 and period number 2 reacts with hydrogen under high pressure and in the presence of a catalyst it terms a hydride (A). In presence of excess of air and in the presence of platinum it forms an oxyacid (B). Identify the element & A and B.

An element A occupies group number 15 and period number 3, reacts with chlorine to give compound B. The compound Bon hydrolysis gives a dibasic acidC. The compound C on heating undergoes auto oxidation and reduction to give a tribasic acid D. Identify the element A, compound B,C and D. Write the reactions.

An element A occupies group number 15 and period number 3, exhibits allotropy and it is tetra atomic. A reacts with caustic soda a to give B which is having rotten fish odour. A reacts with chlorine to give C which has a smell of garlic. Identity A, B and C. Write the reactions.

An element A occupies group number 17 and period number 2, shows anomalous behaviour . A reacts with water forms a mixture of B,C and acid D. B and C are allotropes. A also reacts with hydrogen violently even in dark to given an acid D. Identify A,B,C and D write the reactions.

An element occupies group number 1 and period number 3. This element heated in air gives compound A. With water it gives compound B - a strong base. With ammonia gives compound C, which is used as a reducing agent in organic chemistry. Identify the element A,B and C.