QBManager

PHXII12:ATOMS

356517 As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion:

1 kinetic energy, potential energy and total energy decreases

2 kinetic energy decreases, potential energy increases but total energy remains same

3 kinetic energy and total energy decreases but potential energy increases

4 Its kinetic energy increases but potential energy and total energy decreases

Explanation:

As electron goes to ground state, total energy decreases.
$T E = - K E & P E = 2 T E$
So, kinetic energy increases but potential energy and total energy decreases.

PHXII12:ATOMS

356518 The angular momentum of an electron in first orbit of $L i^{+ +}$ ion is -

1

\frac{3 h}{2 π}

2

\frac{9 h}{2 π}

3

\frac{h}{2 π}

4

\frac{h}{6 π}

Explanation:

Angular momentum $(m v r)$
$= n \cdot \frac{h}{2 π} = \frac{h}{2 π} (n = 1)$

PHXII12:ATOMS

356519 Taking the Bohr radius as $a_{0} = 53 p m,$ the radius of $L i^{+ +}$ ion in its ground state, on the basis of Bohr’s model, will be about

1

27 p m

2

53 p m

3

13 p m

4

18 p m

Explanation:

On the basis of Bohr’s model,
$r = \frac{n^{2} h^{2} ε_{0}}{π m e^{2} Z} = a_{0} \frac{n^{2}}{Z}$
For $L i^{+ +}$ ion, $Z = 3; n = 1$ for ground state
Given, $a_{0} = 53 p m$
$∴ r = \frac{53 \times 1^{2}}{3} = 18 p m$

NCERT Exemplar

PHXII12:ATOMS

356520 Which of the following parameters is same for all hydrogen-like atoms and ions in their ground states?

1 Radius of the orbit

2 Speed of the electron

3 Energy of the atom

4 Orbital angular momentum of the electron

Explanation:

For all $H$ -like atoms in ground state
$L = \frac{h}{2 π}$

PHXII12:ATOMS

356517 As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion:

1 kinetic energy, potential energy and total energy decreases

2 kinetic energy decreases, potential energy increases but total energy remains same

3 kinetic energy and total energy decreases but potential energy increases

4 Its kinetic energy increases but potential energy and total energy decreases

Explanation:

As electron goes to ground state, total energy decreases.
$T E = - K E & P E = 2 T E$
So, kinetic energy increases but potential energy and total energy decreases.

PHXII12:ATOMS

356518 The angular momentum of an electron in first orbit of $L i^{+ +}$ ion is -

1

\frac{3 h}{2 π}

2

\frac{9 h}{2 π}

3

\frac{h}{2 π}

4

\frac{h}{6 π}

Explanation:

Angular momentum $(m v r)$
$= n \cdot \frac{h}{2 π} = \frac{h}{2 π} (n = 1)$

PHXII12:ATOMS

356519 Taking the Bohr radius as $a_{0} = 53 p m,$ the radius of $L i^{+ +}$ ion in its ground state, on the basis of Bohr’s model, will be about

1

27 p m

2

53 p m

3

13 p m

4

18 p m

Explanation:

On the basis of Bohr’s model,
$r = \frac{n^{2} h^{2} ε_{0}}{π m e^{2} Z} = a_{0} \frac{n^{2}}{Z}$
For $L i^{+ +}$ ion, $Z = 3; n = 1$ for ground state
Given, $a_{0} = 53 p m$
$∴ r = \frac{53 \times 1^{2}}{3} = 18 p m$

NCERT Exemplar

PHXII12:ATOMS

356520 Which of the following parameters is same for all hydrogen-like atoms and ions in their ground states?

1 Radius of the orbit

2 Speed of the electron

3 Energy of the atom

4 Orbital angular momentum of the electron

Explanation:

For all $H$ -like atoms in ground state
$L = \frac{h}{2 π}$

PHXII12:ATOMS

356517 As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion:

1 kinetic energy, potential energy and total energy decreases

2 kinetic energy decreases, potential energy increases but total energy remains same

3 kinetic energy and total energy decreases but potential energy increases

4 Its kinetic energy increases but potential energy and total energy decreases

Explanation:

As electron goes to ground state, total energy decreases.
$T E = - K E & P E = 2 T E$
So, kinetic energy increases but potential energy and total energy decreases.

PHXII12:ATOMS

356518 The angular momentum of an electron in first orbit of $L i^{+ +}$ ion is -

1

\frac{3 h}{2 π}

2

\frac{9 h}{2 π}

3

\frac{h}{2 π}

4

\frac{h}{6 π}

Explanation:

Angular momentum $(m v r)$
$= n \cdot \frac{h}{2 π} = \frac{h}{2 π} (n = 1)$

PHXII12:ATOMS

356519 Taking the Bohr radius as $a_{0} = 53 p m,$ the radius of $L i^{+ +}$ ion in its ground state, on the basis of Bohr’s model, will be about

1

27 p m

2

53 p m

3

13 p m

4

18 p m

Explanation:

On the basis of Bohr’s model,
$r = \frac{n^{2} h^{2} ε_{0}}{π m e^{2} Z} = a_{0} \frac{n^{2}}{Z}$
For $L i^{+ +}$ ion, $Z = 3; n = 1$ for ground state
Given, $a_{0} = 53 p m$
$∴ r = \frac{53 \times 1^{2}}{3} = 18 p m$

NCERT Exemplar

PHXII12:ATOMS

356520 Which of the following parameters is same for all hydrogen-like atoms and ions in their ground states?

1 Radius of the orbit

2 Speed of the electron

3 Energy of the atom

4 Orbital angular momentum of the electron

Explanation:

For all $H$ -like atoms in ground state
$L = \frac{h}{2 π}$

PHXII12:ATOMS

356517 As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion:

1 kinetic energy, potential energy and total energy decreases

2 kinetic energy decreases, potential energy increases but total energy remains same

3 kinetic energy and total energy decreases but potential energy increases

4 Its kinetic energy increases but potential energy and total energy decreases

Explanation:

As electron goes to ground state, total energy decreases.
$T E = - K E & P E = 2 T E$
So, kinetic energy increases but potential energy and total energy decreases.

PHXII12:ATOMS

356518 The angular momentum of an electron in first orbit of $L i^{+ +}$ ion is -

1

\frac{3 h}{2 π}

2

\frac{9 h}{2 π}

3

\frac{h}{2 π}

4

\frac{h}{6 π}

Explanation:

Angular momentum $(m v r)$
$= n \cdot \frac{h}{2 π} = \frac{h}{2 π} (n = 1)$

PHXII12:ATOMS

356519 Taking the Bohr radius as $a_{0} = 53 p m,$ the radius of $L i^{+ +}$ ion in its ground state, on the basis of Bohr’s model, will be about

1

27 p m

2

53 p m

3

13 p m

4

18 p m

Explanation:

On the basis of Bohr’s model,
$r = \frac{n^{2} h^{2} ε_{0}}{π m e^{2} Z} = a_{0} \frac{n^{2}}{Z}$
For $L i^{+ +}$ ion, $Z = 3; n = 1$ for ground state
Given, $a_{0} = 53 p m$
$∴ r = \frac{53 \times 1^{2}}{3} = 18 p m$

NCERT Exemplar

PHXII12:ATOMS

356520 Which of the following parameters is same for all hydrogen-like atoms and ions in their ground states?

1 Radius of the orbit

2 Speed of the electron

3 Energy of the atom

4 Orbital angular momentum of the electron

Explanation:

For all $H$ -like atoms in ground state
$L = \frac{h}{2 π}$

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Question Bank Series

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation: