wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

(i) Write the electronic configurations of the following ions: (a) H(b) Na+ (c) O2–(d) F

(ii) What are the atomic numbers of elements whose outermost electrons are represented by (a) 3s1 (b) 2p3 and (c) 3p5?

(iii) Which atoms are indicated by the following configurations?

(a) [He] 2s1 (b) [Ne] 3s2 3p3 (c) [Ar] 4s2 3d1.

Open in App
Solution

(i) (a) H ion

The electronic configuration of H atom is 1s1.

A negative charge on the species indicates the gain of an electron by it.

∴ Electronic configuration of H = 1s2

(b) Na+ ion

The electronic configuration of Na atom is 1s2 2s2 2p6 3s1.

A positive charge on the species indicates the loss of an electron by it.

∴ Electronic configuration of Na+ = 1s2 2s2 2p6 3s0 or 1s2 2s2 2p6

(c) O2– ion

The electronic configuration of 0 atom is 1s2 2s2 2p4.

A dinegative charge on the species indicates that two electrons are gained by it.

∴ Electronic configuration of O2– ion = 1s2 2s2 p6

(d) F ion

The electronic configuration of F atom is 1s2 2s2 2p5.

A negative charge on the species indicates the gain of an electron by it.

∴ Electron configuration of F ion = 1s2 2s2 2p6

(ii) (a) 3s1

Completing the electron configuration of the element as

1s2 2s2 2p6 3s1.

∴ Number of electrons present in the atom of the element

= 2 + 2 + 6 + 1 = 11

∴ Atomic number of the element = 11

(b) 2p3

Completing the electron configuration of the element as

1s2 2s2 2p3.

∴ Number of electrons present in the atom of the element = 2 + 2 + 3 = 7

∴ Atomic number of the element = 7

(c) 3p5

Completing the electron configuration of the element as

1s2 2s2 2p5.

∴ Number of electrons present in the atom of the element = 2 + 2 + 5 = 9

∴ Atomic number of the element = 9

(iii) (a) [He] 2s1

The electronic configuration of the element is [He] 2s1 = 1s2 2s1.

∴ Atomic number of the element = 3

Hence, the element with the electronic configuration [He] 2s1 is lithium (Li).

(b) [Ne] 3s2 3p3

The electronic configuration of the element is [Ne] 3s2 3p3= 1s2 2s2 2p6 3s2 3p3.

∴ Atomic number of the element = 15

Hence, the element with the electronic configuration [Ne] 3s2 3p3 is phosphorus (P).

(c) [Ar] 4s2 3d1

The electronic configuration of the element is [Ar] 4s2 3d1= 1s2 2s2 2p6 3s2 3p6 4s2 3d1.

∴ Atomic number of the element = 21

Hence, the element with the electronic configuration [Ar] 4s2 3d1 is scandium (Sc).


flag
Suggest Corrections
thumbs-up
2
similar_icon
Similar questions
View More
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Electronic Configuration and Orbital Diagrams
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon