Name an element that forms monoclinic crystals. 

Which of the following unit cell is not possible for monoclinic crystals ?

Monoclinic sulphur is an example of monoclinic cystal system. What are the characteristics of the crystal system ?

Monoclinic sulphur is an example of monoclinic cystal system. What are the characteristics of the crystal system ?

Name two elements of group II

Name a non-metallic element which forms an acidic and a neutral oxide.

Name the type of defect that occurs in the crystals of zinc sulphide.

Study the following table in which positions of six elements A,B,C,D,E and F are shown as they are in the modern periodic table. On the basis of the above table, answer the following question : (i) Name the element which form only covalent compounds. (ii) Name the element which is a metal with valency three. (iii) Name the element which is a non-metal with valency three. (iv) Out of D and E, which is bigger in size and why ? (iv) Write the common name for the family to which the elements C and F belongs.

Protoplasmic elements form

Name first element of period 7

Monoclinic crystal has dimension