NEET | JEE | MHT-CET CHEMISTRY | PERIODIC PROPERTIES

       NEET | JEE | MHT-CET CHEMISTRY |

          PERIODIC PROPERTIES

PERIODIC PROPERTIES IMP MCQs WITH SOLUTION

1.         According  to modern   periodic  law, the   chemical  properties   of elements   are the periodic functions of theirs.

            (A) Density                                                                   
          (B) Atomic  number    

           (C) Mass number                                
          (D) Atomic  mass

2.         Downwards in a group, electropositive character of elements.

            (A) Increases                                                              
              (B) Decreases

            (C) Remains  same                                                     
            (D) None

3.         Which of   the following    has the largest   ionic  radius?

            (A) Be +2                     
            (B) Mg +2                                
            (C) Ca +2                   
            (D) Sr +2

4.         The size of  species  l, l+ and l- decreases  in the order

            (A) l+ > l- > l                                                                
             (B)  l- > l > l+

            (C) l- > l+  > l                                                                
            (D)  l >  l+ > l-

5.         Which one of the following   ions has   the smallest   radius ?

            (A) Cl-                           
            (B) S2                                        
            (C) K+                          
            (D) Ca2+

6.         Which one of the following   is the smallest in size?

            (A) N3-                          
             (B)  O2-                        
             (C)  F-                         
            (D) Na+

7.         The correct   order of   second  ionisation  potential   of carbon, nitrogen, oxygen and fluroine is

            (A)  C > N> O > F                                                         
            (B) O > N> F > C

            (C) O > F > N > C                                                        
            (D) F >O > N  > C

8.         The  electronegativity   of the following   elements   increases   in the order

            (A) C, N, Si, P                                                            
            (B) N, Si ,C, P

            (C) Si, P, C, N                                                             
             (D) P, Si, N, C

9.         The radii of F,  F- , O and O2- are in the order of

            (A) O2- > F- > F > O                                                      
           (B)  F-> O2- > F > O

            (C) O2- >  O > F- > F                                                   
           (D) O2- > F- > O > F 

10.       Element X belongs to the 4th period. It contains 18 and 1 electron in the penultimate and the ultimate shell. Therefore X is

            (A) Normal element                                                    
          (B) Transition element

          (C) Inert gas                                                                 
          (D) Inner transition element    

        Answers with Explanation

1.         This is because  fluorine   has got  a  relatively high electron  density   because   of its smaller                      volume and as a result   of this it has  got    lower E. A. than chlorine. That’s why fluoride formation is comparatively difficult.

2.         By giving the   l.P .,Na  is converted to Na+. Now   Na+ has an additional  amount of  energy                    equal to its l.P and in order   to go back  to its original   state - it will  liberate   energy  and              this    we call  as electron affinity.

3.         The alkali metals have one electron in excess of their octet while alkaline earth metals have  2 e ‘s excess of their octet. So after  1st l. P. the alkali metal attains the inert gas configuration while alkaline earth metals attain it after 2nd  l. P.Now removal from a       noble gas core needs high l. P., so there is a jump in the 2nd l. P. for alkali and 3rd l.P. for alkaline earth metals.

4.         While F- is formed   from F  then electron   is added   to an electronegative, neutral  atom and energy (E. A.) is   released  by this process   but even  though O- formation  from O is energy-releasing process, formation   of O2 from  O-  is highly   energy   consuming   . So combined                      effect  is O2- formation  form O  is endothermic.

5.         As we   go down  the period  the electronegativity   decreases   . But after   Al, due to the presence                           of d   electrons   which have   minimum shielding effect, the nuclear charge increases  and hence electronegativity also increases.

6.         From Li to  Be the   additional  electron   is added   in the L shell   which is quite   closer to                          nucleus   whose    the charge   also increases by 1 unit. So greater    force is  experienced by the electrons and size contracts. In going    from Na  to Mg   and K   to Ca   the  electrons                   are added   in M and N shell   respectively    which are  away    from nucleus. Bring                 screening  effects  into account also.

7.         EA = - 3.477 eV

8.         Ionisation   energy   = 11.835 eV, Electron   affinity  = 3.358 eV

9.         Alkaline earth metals have stable ns2 sonfiguration and are reluctant to accept electrons.Thus                        their electron affinity values are eithre small positive or negative.

10.       The energy released in the formation of three bonds as BX3 is more than enough for promoting   of 2s electron to 2p orbital giving 3 equivalent hybrid orbitals lying in a plane at an angle of 120o 

Objective Answer Sheet

1	2	3	4	5	6	7	8	9	10
B	A	D	B	D	D	B	C	A	B