1)

Cấu hình e của X có thể là:

+\(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{ 4}}{{\text{s}}^1}\)

+\(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^5}{\text{ 4}}{{\text{s}}^1}\)

+\(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^{10}}{\text{ 4}}{{\text{s}}^1}\)

2)

Nguyên tố X có 2 e lớp ngoài cùng và có 4 lớp e.

Vậy cấu hình e của X có thể là 

+ \(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{ 4}}{{\text{s}}^2}\)

+ \(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^1}{\text{ 4}}{{\text{s}}^2}\)

+ \(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^2}{\text{ 4}}{{\text{s}}^2}\)

+ \(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^3}{\text{ 4}}{{\text{s}}^2}\)

+\(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^5}{\text{ 4}}{{\text{s}}^2}\)

+ \(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^6}{\text{ 4}}{{\text{s}}^2}\)

+\(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^7}{\text{ 4}}{{\text{s}}^2}\)

+ \(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^8}{\text{ 4}}{{\text{s}}^2}\)

+\(1{s^2}{\text{ 2}}{{\text{s}}^2}2{p^6}{\text{ 3}}{{\text{s}}^2}3{p^6}{\text{3}}{{\text{d}}^{10}}{\text{ 4}}{{\text{s}}^2}\)

1.

Cấu hình e: 

(1) $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$

(2) $1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1$

(3) $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^1$

2.

$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^1 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^2 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^3 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^7 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^8 4s^2$

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2$