Reasons of Stability

Q. The energy required to break one mole of $Cl-Cl$ bonds in $C{l}_2$ is $242{\text{kJ mol}}^{-1}$. The longest wavelength of light capable of breaking a single $Cl-Cl$ bond is:
$(c=3\times {10}^8\text{m/s}\text{and}{N}_A=6.02\times {10}^{23}{\text{mol}}^{-1})$

1. $494\text{nm}$
2. $594\text{nm}$
3. $640\text{nm}$
4. $700\text{nm}$

Q.

The binding energy of an electron in the ground state of an atom is equal to $24.6\mathrm{eV}.$ Find the energy required to remove both the electrons from the atom?

Q. Which state of $B{e}^{3+}$ has the same orbit radius as that of the ground state of hydrogen atom?

1. $3$
2. $2$
3. $4$
4. $5$

Q.

What will happen if alpha particles strike electron in gold foil experiment performed by rutherford?

Q. Different lines in Lyman series of hydrogen spectrum lies in

1. UV
2. far IR
3. Visible
4. IR

Q. The electronic configuration with maximum exchange energy will be

1. $3d_{xy}^{1}3d_{yz}^{1}3d_{zx}^{1}4s^1$
2. $3d_{xy}^{2}3d_{yz}^{2}3d_{zx}^{2}3d_{x^2-y^2}^{2}3d_{z^2}^{1}4s^1$
3. $3d_{xy}^{1}3d_{yz}^{1}3d_{zx}^{1}3d_{x^2-y^2}^{1}3d_{z^2}^{2}4s^2$
4. $3d_{xy}^{2}3d_{yz}^{2}3d_{zx}^{2}3d_{x^2-y^2}^{2}3d_{z^2}^{2}4s^1$

Q. Which of the following orbital has spherical symmetry:

1. $s$ orbital
2. $p$ orbital
3. $d_{xy}$ orbital
4. $d_{z^2}$ orbital

Q. Hydrogen atom has only one electron, so mutual repulsion between electrons is absent. However, in multielectron atoms mutual repulsion between the electrons is significant. How does this affect the energy of an electron in the orbitals of the same principal quantum number in multielectron atoms?

Q. According to Octate Rule, in the outermost shell there can be maximum 8 electrons. But what about the third shell or M-shell, which can occupy 18 electrons

Q. The orbital diagrams of two atoms 'X' and 'Y' are given. Which of the following subshell will be more stable

1. For X, exchange energy is maximum and have more stability
2. For X, exchange energy is minimum and has more stability
3. For Y, exchange energy is maximum and has more stability
4. For Y, exchange energy is minumum and has more stability

Q. The spin-only magnetic moment of a free ion is $\sqrt{8}\text{B.M}$. The spin angluar momentum of the electron is $x\frac{h}{2\pi }$. Find the value of $x^2$.

Q. In the hydrogen atom spectrum, the emission of the least energetic photon takes place during the transition from $n=6$ energy level to $n=$ _______ energy level.

1. $3$
2. $5$
3. $1$
4. $4$
5. $2$

Q. For $1s$ orbital of Hydrogen atom radial wave function is given as:
$R\left(r\right)=\frac{1}{\sqrt{\pi }}{\left(\frac{1}{a_0}\right)}^{3/2}{e}^{-r/a_0}$ where $a_0=0.529A\circ )$
The ratio of radial probability density of finding electron at $r=a_o$ to the radial probability density of finding electron at the nucleus is given as (x.e${}^{-y}$). Calculate the value of (x + y)

Q. What is the maximum number of electrons present in an orbit whose angular momentum is $\frac{3h}{\pi }$?

1. $72$

2. $64$

3. $36$

4. $81$

Q. Assertion :The electronic configurations in which all of the orbitals of the same subshell are either completely filled or are exactly half filled are more stable. Reason: The completely filled or exactly half filled shells possess a symmetrical distribution of electrons and allow their maximum number of exchanges.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. Assertion :The angular momentum of d-orbitals is $\sqrt{6}\frac{h}{2\pi }$. Reason: Angular momentum of $e^{-}$ in orbit is $mvr=\frac{nh}{2\pi }$.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. The ratio of angular momentum in $3$rd orbit and orbital angular momentum of $3d$-orbital is:

1. $\sqrt{\frac{3}{2}}$
2. $\sqrt{\frac{2}{3}}$
3. $\sqrt{6}$
4. $\frac{1}{\sqrt{6}}$

Q. Calculate the radius of Bohr's first orbit for hydrogen atom and the energy of electron in this orbit:

1. -2.178 $\times$ 10${}^{-18}$ J
2. 21.78 $\times$ 10${}^{-18}$ J
3. 2.170 $\times$ 10${}^{-18}$ J
4. 21.88 $\times$ 10${}^{-18}$ J

Q. Is energy of electrons same in same orbit?

Q. Helium nucleus is composed of two protons and two neutrons. If the atomic mass is $4.00388$, how much energy is released when the nucleus is constituted?
(Mass of proton $=1.00757$, Mass of neutron $=1.00893$)

1. $2710MeV$
2. $271MeV$
3. $27.12MeV$
4. $2.71MeV$

Q. The binding energy of an electron in the ground state of an atom is equal to $24.6eV$. Find the energy required to remove both the electrons from the atom.

1. $79eV$
2. $89eV$
3. $99eV$
4. $69eV$

Q.

Lattice energy of an ionic compound depends upon

1. Packing of ions only

2. Charge on the ion and size of the ion

3. Size of the ion only

4. Charge on the ion only

Q.

The neutron was discovered by

1. Marie Curie

2. Pierre Curie

3. James Chadwick

4. Rutherford

Q.

How should we find the number of electron pairs in a molecule like C2H2 using the formula (V+L+A-C)÷2.

WHERE V= VALENCE ELECTRONS, .

L=LIGANDS, .

A=ANIONIC CHARGE,

C=CATIONIC CHARGE, ...???

Q. The difference in angular momentum associated with the electron in two successive orbits of hydrogen atom is xh/2$\pi$.
The value of x is :

Q. The value of Rydberg constant is :

1. $1.09678\times {10}^7$ per meter
2. $1.09876\times {10}^7$ per meter
3. $1.07876\times {10}^7$per meter
4. $1.07678\times {10}^7$per meter

Q. Calculate the number of neutrons in $18mL$ of water. (Density of water $=1$).

Q. A body of mass 'M'is revolving in a vertical circle of radius 'R' what is the difference in the kinetic energies at the bottom and top portion of the circle?

Q. The difference in angular momentum of electrons between any two successive orbits in an atom is :

1. $\frac{h}{2\pi }$
2. $\frac{2h}{3\pi }$
3. $\frac{3h}{5\pi }$
4. Cannot be determined

Q. If a metal is irradiated with light of frequency $3\times {10}^{19}$ sec${}^{-1}$, the electron is emitted with a kinetic energy of $6.625\times {10}^{-15}$ J. The threshold frequency of the metal is

1. $2\times {10}^{19}$ sec${}^{-1}$
2. $6.625\times {10}^{35}$ sec${}^{-1}$
3. $1.25\times {10}^{19}$ sec${}^{-1}$
4. $6.625\times {10}^{19}$ sec${}^{-1}$