classification of elements, chemical bonding, periodicity in properties & physical transformation - Category wise Question and Answer Practice Test with Solutions

Question : 21

Which of the following properties do not match elements of halogen family ?

a) They are diatomic in their molecular form

b) They are highly reactive chemically

c) They have seven electrons in their valence shell

d) They are metallic in nature

Question : 22 [BPSC (Pre) 1992]

Pasteurization is a process by which

a) Milk is heated for 8 hours

b) First milk is heated up to a longer time and then cooled suddenly within specified time

c) Milk is preserved at a very low temperature for 24 hours

d) None of the above

Question : 23 [CDS ]

The elements of a group in the periodic tabic

a) have consecutive atomic numbers

b) are isobars

c) have similar chemical properties

d) are isotopes

Question : 24

Which one of the following elements exhibit maximum number of valence electrons?

a) Al

b) Si

c) Na

d) P

Question : 25 [BPSC (Pre) 2000]

Process of solid camphor into camphor vapour is called

a) Freezing

b) Melting

c) Vaporisation

d) Sublimation