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 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.

BF_(3) reacts with LiH and forms a compound A. The compound A reacts with water to give the compound B. A reacts with ammonia at 390 K and form C. Identify (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 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 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 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 when exposed to air gives compound (A). The element with water forms compound (B). Which is a strong base und (A) with ammonia gives compound (C ) which is used as reducing agent in organic chemistry. The element reacts with an halogen and forms cooking salt (D). Identify A, B, C and D.

An element A occupies group number 15 and period number 3, exhibits allotropy and it is tetra atomic. A reacts with caustic soda to give B which is having rotten fish odour. A reacts with chlorine to give C which has a pungent odour. Identify A, B and 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.