Aufbau Principle

Q.

Explain Aufbau Principle with an example.

Q. After np obitals are filled, the next orbital to be filled will be

1. (n + 1)s
2. (n+2)p
3. (n+1)d
4. (n+2)s

Q.

Electrons in an orbital are filled according to which rule?

Q. Which of the following atoms violate Aufbau principle?

1. Cu
2. Cr
3. N
4. Both A and B

Q. Match the following:

Rules	Statements
A) Hund's rule of maximum multiplicity	P) No two electrons in an atom can have the same set of quantum numbers
B) Aufbau principle	Q) Half-filled and completely filled orbitals have extra stability
C) Pauli's exclusion principle	R) Pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital is singly occupied
D) Hiesenberg's Uncertainity Principle	S) It is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously
	T) In the ground state of atoms, orbitals are filled in the order of their increasing energies

1. $A)-R),B)-T),C)-P),D)-S)$
2. $A)-S),B)-T),C)-Q),D)-R)$
3. $A)-R),B)-T),C)-S),D)-P)$
4. $A)-S),B)-P),C)-T),D)-Q)$

Q.

Statement - I: $Cd$ is a transition element.
Statement - II: $Cd$ and $C{d}^{2+}$ both have completely filled $d-$ orbitals in their ground state.

1. Statement - I is true; Statement - II is true; Statement - II is correct explanation for Statement - I

2. Statement - I is true; Statement - II is true; Statement - II is NOT the correct explanation for Statement - I

3. Statement - I is true; Statement - II is false

4. Statement - I is false; Statement - II is true

Q.

How is the order of energy of atomic orbitals established?

Q. The electronic configurations of four elements are given below. Which of the corresponding elements has maximum total electronic spin?

1. $1s^{2}2s^{2}2p^6$
2. $1s^{2}2s^{2}2p^1$
3. $1s^{2}2s^{2}2p^5$
4. $1s^{2}2s^{2}2p^4$

Q. If aufbau rule in not followed, the ${19}^{th}$ electron of Sc(Z=21) will have:

1. n=3, l=0
2. n=3, l=0
3. n=3, l=2
4. n=4, l=0

Q. Which is the correct order of increasing energy of the listed orbitals in the atom of titanium ? (At. no. $Z=22$)

1. $3s3p3d4s$
2. $3s3p4s3d$
3. $3s4s3p3d$
4. $4s3s3p3d$

Q.

Which one of the following configuration represents a noble gas

1. $1s^2,2s^{2}2p^6,3s^2$

2. $1s^2,2s^{2}2p^6,3s^1$

3. $1s^2,2s^{2}2p^6$

4. $1s^2,2s^{2}s{p}^6,3s^{2}3p^6,4s^2$

Q. The electronic configuration of $C{a}^{2+}$ is:

1. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$
2. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^1$
3. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$
4. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^0$

Q.

Which of the following orbital has most energy in multi-electron system?

1. 3s

2. 4p

3. 4d

4. 4s

Q. According to Aufbau principle, the increasing order of energies of 3d, 4s, and 4p orbitals is:

1. 4p < 3d < 4s
2. 4s < 4p < 3d
3. 4s < 3d < 4p
4. 3d < 4s < 4p

Q. Identify the correct statements among the following:

1. If Aufbau principle is not followed, then $Sn$ (atomic number = 50) would be placed in $d-$ block of the periodic table
2. $5^{th}$ ionization energy of $As$ $(Z=33)$ is less than that of $Ge(Z=32)$
3. Increasing order of first ionization energy of $S,Se$ and $Cl$ is $Se<S<Cl$
4. Ionic radii of $M{g}^{2+}(Z=12)$ is smaller than $F^{-}(Z=9)$

Q. The electrons, identified by quantum number n and l,
(i) n = 4, l = 1(ii) n = 4, l = 0(iii) n = 3, l = 2 and (iv) n = 3, l = 1
Can be placed in order of increasing energy, from lowest to highest as

1. (i) < (iii) < (ii) < (iv)

2. (ii) < (iv) < (i) < (iii)

3. (iv) < (ii) < (iii) < (i)

4. (iii) < (i) < (iv) < (ii)

Q. Which of the following will show paramagnetism?

1. $Ar$
2. $Ti$
3. $S{c}^{3+}$
4. $V^{5+}$

Q.

The ratio of atomic numbers of two elements ‘ P’ and Q is 2:7. The energy of the fourth orbit of single-electron species of P is $-13.6\mathrm{e}/\mathrm{v}.$ Calculate the difference in the number of electrons present in the valence and penultimate shells of Q.

1. 2

2. 4

3. 3

4. 1

Q. Which of the following orbitals described by three quantum numbers will have different energies for a multielectron atom, in the absence of external electric and magnetic fields?
$\text{(1) n = 1, l = 0, m = 0}$
$\text{(2) n = 2, l = 1, m = -1}$
$\text{(3) n = 2, l = 1, m = +1}$
$\text{(4) n = 3, l = 2, m = +1}$
$\text{(5) n = 3, l = 2, m = 0}$

1. $\text{4 and 5}$
2. $\text{1 and 2}$
3. $\text{2 and 3}$
4. $\text{None of these}$

Q. The following questions consist of two statements. Select the correct option for these statements:
Statement 1: The first ionization energy of $Be$ is greater than that of $B$.
Statement 2: $2p$-orbital is lower in energy than $2s$.

1. Both the statements are CORRECT, and Statement II is the CORRECT explanation of Statement I
2. Both the statements are CORRECT, and Statement II is not a CORRECT explanation of Statement I
3. If Statement I is CORRECT, but Statement II is INCORRECT
4. If Statement I is INCORRECT, but Statement II is CORRECT

Q. The electrons, identified by quantum number n and l,
(i) n = 4, l = 1(ii) n = 4, l = 0(iii) n = 3, l = 2 and (iv) n = 3, l = 1
Can be placed in order of increasing energy, from lowest to highest as

1. (i) < (iii) < (ii) < (iv)

2. (ii) < (iv) < (i) < (iii)

3. (iv) < (ii) < (iii) < (i)

4. (iii) < (i) < (iv) < (ii)

Q. For a $3s-$ orbital
$\Psi \left(3s\right)=\frac{1}{9\sqrt{3}}{\left(\frac{1}{a_0}\right)}^{\frac{3}{2}}(6-6\sigma +{\sigma }^2)e^{\frac{-\sigma }{2}};\text{where}\sigma =\frac{2r.Z}{3a_0}$
What is the maxium radial distance of node from nucleus?

1. $\frac{(3+\sqrt{3})a_0}{Z}$
2. $\frac{a_0}{Z}$
3. $\frac{3}{2}\times \frac{(3+\sqrt{3})a_0}{Z}$
4. $\frac{2a_0}{Z}$

Q. How many shells, orbitals and electrons are there in an atom having atomic mass 24 and atomic number 12 respectively?