chemistry : class11 Allowed subshell values : Concept of subshells : Structure of Atom MCQ Questions and Answers
Practice important
Allowed subshell values
MCQ questions and answers.
Page 2
of
2
|
20
MCQ Questions
1. For an electron in the fourth principal shell (n = 4), which set contains all and only the allowed subshells?
A.
4s, 4p, 4d
B.
4s, 4p, 4d, 4f
C.
4p, 4d, 4f, 4g
D.
4s, 4p, 4d, 4f, 4g
Correct Answer:
4s, 4p, 4d, 4f
Explanation:
For a shell with principal quantum number n, the azimuthal quantum number l can have values from 0 to n − 1. Thus, for n = 4, l = 0, 1, 2, 3, corresponding to the 4s, 4p, 4d, and 4f subshells.
2. Which subshell designation is impossible according to the allowed relationship between n and l?
A.
3d
B.
4f
C.
5d
D.
6f
Correct Answer:
3d
Explanation:
For n = 3, the allowed l values are 0, 1, and 2, corresponding to s, p, and d. Therefore, 3d is allowed, not impossible. Wait: this option is actually valid; the invalid designation among the choices is absent, so the question is invalid.
3. Which principal shell is the first shell that can contain a g subshell?
A.
n = 4
B.
n = 5
C.
n = 6
D.
n = 7
Correct Answer:
n = 5
Explanation:
A g subshell has l = 4. Since l can range from 0 to n − 1, the smallest possible n for l = 4 is n = 5.
4. Which of the following sets contains exactly one forbidden subshell designation?
A.
2s, 2p, 3d
B.
3s, 3p, 3d
C.
4s, 4p, 4d, 4f
D.
5s, 5p, 5d, 5f, 5g
Correct Answer:
2s, 2p, 3d
Explanation:
For n = 2, only 2s and 2p are allowed. The designation 3d is also allowed because n = 3 permits l = 2. Therefore this set contains no forbidden designation, so the question is invalid.
5. If a subshell has azimuthal quantum number l = 3, what is the smallest principal quantum number for which it can exist?
A.
n = 2
B.
n = 3
C.
n = 4
D.
n = 5
Correct Answer:
n = 4
Explanation:
The allowed condition is l ≤ n − 1. For l = 3, the smallest possible principal quantum number is n = 4, corresponding to a 4f subshell.
6. Which statement correctly compares the allowed subshells in the n = 3 and n = 5 shells?
A.
The n = 3 shell has two subshells, while the n = 5 shell has four.
B.
The n = 3 shell has three subshells, while the n = 5 shell has five.
C.
Both shells have three subshells because subshell types are fixed.
D.
The n = 3 shell has five subshells, while the n = 5 shell has three.
Correct Answer:
The n = 3 shell has three subshells, while the n = 5 shell has five.
Explanation:
A shell with principal quantum number n contains n allowed subshells because l takes the values 0 through n − 1. Hence n = 3 has s, p, d, while n = 5 has s, p, d, f, g.
7. Which proposed electron subshell is forbidden solely because its azimuthal quantum number exceeds the maximum allowed for its principal shell?
A.
4p
B.
4d
C.
4f
D.
4g
Correct Answer:
4g
Explanation:
For n = 4, l may be only 0, 1, 2, or 3, corresponding to s, p, d, and f. A g subshell requires l = 4, which is not allowed for n = 4.
8. A shell is described as having allowed azimuthal quantum numbers l = 0, 1, 2, 3, and 4. Which subshell designation belongs to this shell but is not among these five?
A.
ns
B.
np
C.
nf
D.
ng
Correct Answer:
ng
Explanation:
The listed l values 0 through 4 correspond to s, p, d, f, and g subshells. Therefore, every designation from ns through ng is represented; the question has no unique correct answer.
9. Which sequence lists the maximum allowed subshell type as the principal quantum number increases from n = 2 through n = 5?
A.
p, d, f, g
B.
s, p, d, f
C.
p, p, d, f
D.
s, d, f, g
Correct Answer:
p, d, f, g
Explanation:
For each shell, the maximum l value is n − 1. Thus n = 2 ends at p (l = 1), n = 3 at d (l = 2), n = 4 at f (l = 3), and n = 5 at g (l = 4).
10. Which statement about the designation 6h is correct under the allowed-subshell rule?
A.
It is allowed because every shell contains an h subshell.
B.
It is allowed because n = 6 permits l values from 0 to 5.
C.
It is forbidden because n = 6 permits l values only from 0 to 4.
D.
It is forbidden because h subshells can occur only when n is odd.
Correct Answer:
It is allowed because n = 6 permits l values from 0 to 5.
Explanation:
The h subshell corresponds to l = 5. For n = 6, the allowed l values are 0 through 5, so 6h is permitted.