Bohr model

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Why was the picture of atoms called the planetary model?

Because it suggested that electrons have a fixed position within the nucleus.

Because it depicted the electron as orbiting the nucleus like planets orbiting the sun. (correct)

Because it showed the electrons moving randomly around the nucleus.

Because it demonstrated the movement of electrons in a straight line.

What is the simplest atom according to the text?

Hydrogen (correct)

Oxygen

Nitrogen

Carbon

Why did Niels Bohr ignore classical electromagnetism's prediction regarding the orbiting electron in hydrogen?

To prevent the electron from spiraling into the nucleus. (correct)

To accelerate the electron's movement.

To increase the size of the electron's orbit.

To increase the stability of atoms.

What would happen if an electron were to move in an elliptical orbit according to classical electromagnetism?

It would continuously emit electromagnetic radiation. Signup and view all the answers

How did Niels Bohr incorporate Planck's ideas and Einstein's finding into the classical mechanics description of the atom?

By considering light as consisting of photons with energy proportional to frequency. Signup and view all the answers

Why is the classical mechanics description of the atom, as mentioned in the text, considered incomplete?

Because it does not account for continuous emission of electromagnetic radiation by an accelerating electron. Signup and view all the answers

According to Bohr's model, when is a photon emitted or absorbed by an electron?

When the electron moves to a different orbit Signup and view all the answers

What does the expression En = -k*n^2 represent in Bohr's model of the atom?

The quantized energy levels of an electron orbital Signup and view all the answers

What happens to an atom when its electron moves to a higher energy orbit?

It is in an excited state Signup and view all the answers

How does the energy expression differ for hydrogen-like atoms compared to hydrogen atoms?

The nuclear charge is different in hydrogen-like atoms Signup and view all the answers

What is implied by the equation r = n^2Za0 for the circular orbits of hydrogen-like atoms?

Electrons are found at greater distances from the nucleus as n increases Signup and view all the answers

Why did Bohr's model get taken seriously despite its many assumptions?

Because it agreed excellently with experimental results for the Rydberg constant Signup and view all the answers

What does the ionization limit represent when n ⟶ ∞ and r ⟶ ∞?

The electron is completely removed from the nucleus Signup and view all the answers

Why was Bohr's model of the hydrogen atom considered flawed?

It was based on classical mechanics notions of precise orbits Signup and view all the answers

What does the energy difference between two states indicate during an electron transition?

A photon is absorbed Signup and view all the answers

In Bohr's model, what is used to describe the quantized energies of electrons in an atom?

Quantum numbers with specific allowed values Signup and view all the answers

What does the calculated energy of an electron in a hydrogen atom at n = 3 represent?

Excitation to a higher energy level Signup and view all the answers

What happened when Bohr tried to extend his theory to the next simplest atom, helium (He)?

He encountered difficulties due to interactions between electrons Signup and view all the answers

What does the wavelength of a photon during an electron transition indicate?

Its energy Signup and view all the answers

How did physicists at the time perceive classical theories after resolving paradoxes involving Planck's constant?

They were fundamentally flawed for atoms and molecules Signup and view all the answers

What is the significance of the ionization limit when n tends to infinity and the orbit radius tends to infinity?

It corresponds to the energy where the electron is completely removed from the nucleus. Signup and view all the answers

Why was Bohr's model considered flawed according to the text?

It was based on classical mechanics concepts which were later found to be untenable at the microscopic level. Signup and view all the answers

In Bohr's model, what does a negative energy value for an electron indicate?

The electron is in a stable orbit. Signup and view all the answers

What was the major limitation of Bohr's model in extending it to atoms with more than one electron?

It did not consider electron-electron interactions. Signup and view all the answers

How did early researchers calculate the energy of an electron at a specific distance from the nucleus in a hydrogen atom?

By using classical mechanics principles. Signup and view all the answers

What does a positive energy difference between two states indicate during an electron transition?

Energy is absorbed as a photon. Signup and view all the answers

Why did classical mechanics concepts fail to extend into the microscopic domain according to most physicists at that time?

They could not properly account for phenomena at the atomic scale. Signup and view all the answers

What is the calculated energy, in joules, of an electron in a hydrogen atom when it is promoted to an orbit with n = 3?

-2.421 × 10^-19 J Signup and view all the answers

What is the energy, in joules, and the wavelength, in meters, of the photon produced when an electron falls from the n = 4 to the n = 6 level in a hydrogen atom?

Energy: 7.566 × 10^-20 J; Wavelength: 2.626 × 10^-6 m Signup and view all the answers

What is the energy, in joules, and the wavelength, in meters, of the photon produced when an electron falls from the n = 5 to the n = 3 level in a He+ ion (Z = 2 for He+)?

Energy: 6.198 × 10^-19 J; Wavelength: 3.205 × 10^-7 m Signup and view all the answers

Why was Bohr unable to extend his model to the next simplest atom, helium (He), which only has two electrons?

Bohr's model was based on the flawed concept of precise orbits from classical mechanics, which did not hold true in the microscopic domain of atoms with more than one electron. Signup and view all the answers

What does the ionization limit represent when n tends to infinity and the orbit radius tends to infinity?

The ionization limit corresponds to an energy of 0, indicating that the electron is completely removed from the nucleus. Signup and view all the answers