Answer:

Answer

(i) (a) The electronic configuration of H

−

is 1s

2

(b)The electronic configuration of Na

+

is 1s

2

2s

2

2p

6

(c)The electronic configuration of O

2−

is 1s

2

2s

2

2p

6

(d) The electronic configurations of F

−

is 1s

2

2s

2

2p

6

(ii) The atomic numbers of elements whose outermost electrons are represented by (a)3s

1

(b)2p

3

and(c)3d

1

are 11 (Na), 7 (N) and 21 (Sc) respectively.

(iii) The following configurations indicates

(a) [He]2s

1

(b) [Ne]3s

2

3p

3

(c) [Ar]4s

2

3d

1

(a) Li (Z=3), (b) P(Z=15) and (c) Sc Z=21) respectively.

Explanation:

Answer

(i) (a) The electronic configuration of H

−

is 1s

2

(b)The electronic configuration of Na

+

is 1s

2

2s

2

2p

6

(c)The electronic configuration of O

2−

is 1s

2

2s

2

2p

6

(d) The electronic configurations of F

−

is 1s

2

2s

2

2p

6

(ii) The atomic numbers of elements whose outermost electrons are represented by (a)3s

1

(b)2p

3

and(c)3d

1

are 11 (Na), 7 (N) and 21 (Sc) respectively.

(iii) The following configurations indicates

(a) [He]2s

1

(b) [Ne]3s

2

3p

3

(c) [Ar]4s

2

3d

1

(a) Li (Z=3), (b) P(Z=15) and (c) Sc Z=21) respectively.