`""_(11)Na=1s^(2) 2s^(2)2p^(6) 3s^(1)`
`""_(21) Sc=1s^(2)2s^(2)2p^(6) 3s^(2)3p^(6) 4s^(2)3d^(1)`
Which one can form cation rasily ? Why ?

""_(11)Na=1s^(2) 2s^(2)2p^(6) 3s^(1) ""_(21) Sc=1s^(2)2s^(2)2p^(6) 3s^(2)3p^(6) 4s^(2)3d^(1) Write the group and periods of the given elements.

""_(21 ) Sc : 1s^(2 ) 2s ^(2) 2p ^(6) 3s^(2)3p ^(6 ) 4s ^(2) 3d^(1) Scandium belongs to which block ?

Sc = 1s^2 2s^2 2p^6 3s^2 3p^6s 4s^2 3d^1 .this is belongs to

1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(5) is not the electron configuration of

Consider the following list of electron configurations: (1) 1s^(2)2s^(2)3s^(2) (2) 1s^(2)2s^(2)2p^(6) (3) 1s^(2)2s^(2)2p^(6)3s^(1) (4) 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2) (5) 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(6) Which one of the above configuration represents a neutral atom that readily forms a singly charged positive ion?

Consider the following list of electron configurations: (1) 1s^(2)2s^(2)3s^(2) (2) 1s^(2)2s^(2)2p^(6) (3) 1s^(2)2s^(2)2p^(6)3s^(1) (4) 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2) (5) 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(6) Which one of the above configurations represents an excited state of a neutral atom?

Consider the following list of electron configurations: (1) 1s^(2)2s^(2)3s^(2) (2) 1s^(2)2s^(2)2p^(6) (3) 1s^(2)2s^(2)2p^(6)3s^(1) (4) 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2) (5) 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(6) Which one of the above configuration represents a transition element?

Elements A, B, C, D and E have the following electronic configurations: A: 1s^(2) 2s^(2) 2p^(1) B: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(1) C: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(2) D: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(5) E: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2) Which among these will belong to the same group in the periodic table?

Elements A, B, C, D and E have the following electronic configurations: A: 1s^(2) 2s^(2) 2p^(1) B: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(1) C: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(2) D: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(5) E: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2) Which among these will belong to the same group in the periodic table?

The electronic configurations of some elements are given below: (i) 1s ^(2) 2s ^(2) 2p ^(6) 3s ^(1) (ii) 1s ^(2) 2s ^(2) 2p ^(6) 3s ^(2) 3p ^(6) 4s ^(2) 3s ^(1) (iii) 1s ^(2) 2s ^(2) 2p ^(3) (iv) 1s ^(2) 2s ^(2) 2p ^(6) 3s ^(2) 3p ^(6) 4s ^(2) (v) 1s ^(2) 2s ^(2) 2p ^(6) 3s^(2) 3p ^(5) (vi ) 1s ^(2) 2s ^(2) 2p^(6) 3s ^(2) 3p ^(3) (vii) 1s^(2) 2s ^(2) 2p^(6) (viii) 1s ^(2) 2s ^(2) 2p ^(6) 3s ^(2) 3p ^(4) Name the elements. Out of these which 1. is an alkaline earth metal 2. has lowest chemical reactivity 3. belong to group 15 of the periodic table 4. is a transition element 5. is halogen 6. belong to p-block 7. belong to second period.