Bohr Model of the Atom Quiz- general chem 2

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

What does the Rydberg constant primarily relate to?

  • The energy levels in an atom
  • The mass of the electron
  • The charge of the electron
  • The wavelengths of spectral lines in hydrogen (correct)

What is the value of the Bohr radius, $a_0$, for the hydrogen atom?

  • $1.00 \times 10^{-10} m$
  • $2.18 \times 10^{-11} m$
  • $3.56 \times 10^{-10} m$
  • $5.29 \times 10^{-11} m$ (correct)

Which transition between energy levels in hydrogen would release the most energy?

  • From n=7 to n=1 (correct)
  • From n=3 to n=2
  • From n=4 to n=1
  • From n=5 to n=3

What equation is used to find the energies of photon transitions between atomic levels?

<p>$E = \frac{hcR}{n^2_{Upper} - n^2_{Lower}}$ (B)</p> Signup and view all the answers

What is a limitation of the Bohr model?

<p>It can only describe hydrogen-like atoms (A)</p> Signup and view all the answers

What does 'R' represent in the energy equation for spectral lines?

<p>Rydberg constant (C)</p> Signup and view all the answers

Which series in the hydrogen spectrum corresponds to transitions ending at n=1?

<p>Lyman series (D)</p> Signup and view all the answers

Which of the following correctly describes hydrogen-like atoms?

<p>They contain only one electron but can have a different nuclear charge (D)</p> Signup and view all the answers

Which of the following describes a limitation of the Bohr model?

<p>It does not account for electron spin. (A)</p> Signup and view all the answers

In the Bohr model, what quantizes the angular momentum of an electron?

<p>The principal quantum number n (B)</p> Signup and view all the answers

The formula for the energy levels in the hydrogen atom can be rewritten in terms of which constant?

<p>Rydberg constant (B)</p> Signup and view all the answers

In which series do the spectral lines of hydrogen transitions occur in the visible region?

<p>Balmer series (C)</p> Signup and view all the answers

How does the Bohr model explain the line spectrum of hydrogen?

<p>By allowing electrons to fall between defined energy levels (D)</p> Signup and view all the answers

What is the formula for the momentum of an electron in the Bohr model?

<p>$p = nh/2\pi r$ (D)</p> Signup and view all the answers

What does the principal quantum number 'n' represent in the Bohr model?

<p>The size of the orbital. (D)</p> Signup and view all the answers

Which of the following statements about hydrogen-like atoms is true?

<p>Their energy levels can be predicted using the Bohr model. (D)</p> Signup and view all the answers

What factor influences the energy difference between levels in hydrogen-like atoms?

<p>The charge of the nucleus (B)</p> Signup and view all the answers

What condition must be satisfied for the electron in the Bohr model?

<p>The angular momentum must be a fraction of $h$ (B)</p> Signup and view all the answers

Which term in the energy formula accounts for the attractive force between the positively charged nucleus and the negatively charged electron?

<p>Potential energy (Un) (A)</p> Signup and view all the answers

What is the relationship between the Bohr radius and the principal quantum number 'n'?

<p>The Bohr radius is directly proportional to 'n'. (A)</p> Signup and view all the answers

What is the calculated wavelength for a transition from n=3 to n=2 in hydrogen according to the Bohr model?

<p>656.3 nm (B)</p> Signup and view all the answers

Which element's spectral lines can be explained by the Bohr model?

<p>Hydrogen (H) (A)</p> Signup and view all the answers

What is the Rydberg constant value used in the wavelength calculations for hydrogen?

<p>1.097 x 10^7 m^-1 (C)</p> Signup and view all the answers

How does the Bohr model modify for a singly-ionized helium atom compared to hydrogen?

<p>Energy levels are adjusted by Z². (B)</p> Signup and view all the answers

Which of the following limitations does the Bohr theory not address?

<p>Mass of the electron. (D)</p> Signup and view all the answers

The Balmer Hα line corresponds to which transition?

<p>n=3 to n=2 (D)</p> Signup and view all the answers

What is true of the visible part of the hydrogen spectrum?

<p>It only includes the Balmer series. (B)</p> Signup and view all the answers

Which series of spectral lines is not observed in the hydrogen spectrum?

<p>Davison series (D)</p> Signup and view all the answers

In the Bohr model, what is the effect of increasing the principal quantum number (n) on the energy level of an electron?

<p>Energy increases as n². (C)</p> Signup and view all the answers

The transitions of electrons in the Bohr model primarily explain...

<p>Energy emission and absorption in hydrogen. (C)</p> Signup and view all the answers

What directly influences the amount of energy released during an electron's fall to a lower energy orbit in the Bohr model?

<p>The size of the energy gap (B)</p> Signup and view all the answers

In Bohr's model, how is the angular momentum of an electron expressed mathematically?

<p>L = nh/2Ï€ (C)</p> Signup and view all the answers

What relationship does the de Broglie wavelength of an electron have with its momentum according to the Bohr model?

<p>λ = h/p (C)</p> Signup and view all the answers

Which equation represents the balance of electrostatic and centripetal forces acting on the electron in a hydrogen atom according to the Bohr model?

<p>$F_e = F_c$ (D)</p> Signup and view all the answers

What type of atom does the original Bohr model primarily focus on?

<p>Hydrogen-like atoms (C)</p> Signup and view all the answers

Which of the following variables is NOT part of the quantized angular momentum equation in the Bohr model?

<p>Orbital radius (r) (C)</p> Signup and view all the answers

According to the Bohr model, what physical principle explains the quantization of orbits for the electron?

<p>Quantization of angular momentum (D)</p> Signup and view all the answers

In the context of the Bohr model, what does the term 'electron transition' refer to?

<p>An electron changing orbits (D)</p> Signup and view all the answers

What physical concept does the de Broglie wavelength represent in relation to an electron in orbit?

<p>The spatial distribution of the electron (A)</p> Signup and view all the answers

Which concept from the Bohr model reflects the relationship between the electron's speed and its distance from the nucleus?

<p>Speed increases with decreasing distance (A)</p> Signup and view all the answers

What does the symbol $a_0$ represent in the context of the Bohr model?

<p>Minimum radius of an electron orbital (D)</p> Signup and view all the answers

In the Bohr model, what does an increase in the principal quantum number $n$ result in?

<p>Higher energy and larger radial distances (C)</p> Signup and view all the answers

What is the significance of the Rydberg constant $R$ in the Bohr model?

<p>It relates to the energy levels of the hydrogen atom (A)</p> Signup and view all the answers

How is energy calculated for photon transitions between energy levels?

<p>$E = hcR( \frac{1}{n_{Upper}^2} - \frac{1}{n_{Lower}^2})$ (B)</p> Signup and view all the answers

What does the negative value in the energy expression $E_n = -\frac{me^4}{8e_0^2h^2n^2}$ indicate?

<p>Energy is bound to the atom (B)</p> Signup and view all the answers

Which equation describes the momentum of an electron in the context of the Bohr model?

<p>$p = mvr = n \frac{h}{2\pi}$ (D)</p> Signup and view all the answers

What energy level corresponds to the transition from $n=3$ to $n=2$ in hydrogen?

<p>1.89 eV (D)</p> Signup and view all the answers

How is the allowed energy for an electron in the Bohr model derived?

<p>By summing potential energy and kinetic energy (D)</p> Signup and view all the answers

What is the term for the energy associated with the position of the electron in the atom?

<p>Potential Energy (D)</p> Signup and view all the answers

In the context of the Bohr model, which factor primarily determines the size of electron orbits?

<p>Principal quantum number (A)</p> Signup and view all the answers

What is the wavelength calculated for a transition from n=3 to n=2 in hydrogen?

<p>656.3 nm (C)</p> Signup and view all the answers

How does the Bohr model of hydrogen compare to multi-electron atoms?

<p>It fails to account for their complexities. (C)</p> Signup and view all the answers

In the context of the Bohr model, what does the term 'n' represent?

<p>The quantum state of the electron (C)</p> Signup and view all the answers

What modification is made to the Bohr formula for singly-ionized helium?

<p>En → ZEn (D)</p> Signup and view all the answers

Which emission line corresponds to the transition from n=2 to n=1 in hydrogen?

<p>Lyman series (A)</p> Signup and view all the answers

Which of the following observations does the Bohr model explain accurately?

<p>Wavelength of the Balmer Hα line (B)</p> Signup and view all the answers

What is the significance of the Rydberg constant in atomic spectra?

<p>Determines the wavelength of emitted light (D)</p> Signup and view all the answers

What limitation does the Bohr model have regarding spectral lines?

<p>It fails to indicate the rate of transitions. (D)</p> Signup and view all the answers

For which atom does the Bohr model not provide an adequate description?

<p>Lithium (C)</p> Signup and view all the answers

Which series of spectral lines is not visible in hydrogen's spectrum?

<p>UV series (D)</p> Signup and view all the answers

Flashcards

Bohr model of Hydrogen

A theoretical model that describes the structure of the hydrogen atom. It suggests electrons orbit the nucleus in specific, quantized energy levels.

Rydberg equation

A formula used to calculate the wavelengths of spectral lines in hydrogen-like atoms.

Rydberg constant

A fundamental constant in physics, used in the Rydberg equation. It relates to the energy levels and wavelengths in Hydrogen-like atoms.

Hydrogen spectral lines

Distinct frequencies of light emitted by a hydrogen atom when its electrons transition between energy levels.

Signup and view all the flashcards

Hydrogen-like atoms

Atoms with a single electron, such as hydrogen and singly ionized helium.

Signup and view all the flashcards

Balmer Hα line

A specific spectral line in the visible light spectrum of hydrogen, calculated using the Rydberg equation.

Signup and view all the flashcards

Limitations of Bohr Theory

The Bohr model, while successful for hydrogen, fails to accurately predict the spectra of more complex atoms.

Signup and view all the flashcards

Atomic spectra

The pattern of spectral lines emitted by atoms, when electrons are excited and transition between energy levels.

Signup and view all the flashcards

Electron transitions

The movement of an electron between different energy levels in an atom.

Signup and view all the flashcards

Quantum mechanics (QM)

A more generalized and accurate theory that explains atomic and molecular behavior, and where the Bohr model is insufficient to fully explain.

Signup and view all the flashcards

Quantized Angular Momentum

The angular momentum of an electron in an atom can only take on certain discrete values. Specific amounts.

Signup and view all the flashcards

Electron Orbits

Electrons in atoms don't travel randomly, but in specific, pre-defined paths or orbits around the nucleus.

Signup and view all the flashcards

Line Spectrum

A spectrum with specific lines/colors representing energy levels.

Signup and view all the flashcards

Energy Levels

Distinct energy states associated with the allowed electron orbits.

Signup and view all the flashcards

Quantization

The concept that certain physical properties (in this case, energy and angular momentum) can only take on specific, distinct values, like steps on a staircase.

Signup and view all the flashcards

de Broglie Waves

Waves associated with particles, in this case, the electron.

Signup and view all the flashcards

Standing Wave

A wave that appears to stay in one place, not moving forward or backward, because its ends are fixed.

Signup and view all the flashcards

Electrostatic Force

The force of attraction between opposite charges.

Signup and view all the flashcards

Centripetal Force

The force that keeps an object moving in a circular path.

Signup and view all the flashcards

Bohr radius (a0)

The smallest possible radius of an electron's orbit in a hydrogen atom, according to the Bohr model.

Signup and view all the flashcards

Principal quantum number (n)

An integer that determines the energy level and radius of an electron's orbit in the Bohr model. Higher 'n' means larger radius and higher energy.

Signup and view all the flashcards

What is the Bohr model's main idea?

It proposes that electrons orbit the nucleus in specific, quantized energy levels and can jump between these levels by absorbing or emitting photons of light.

Signup and view all the flashcards

What is the energy equation in Bohr's model?

The energy of an electron in a hydrogen atom is given by En = -me^4/(8ε0^2h^2n^2), where 'n' is the principal quantum number.

Signup and view all the flashcards

How does the Bohr model explain spectral lines?

When an electron jumps from a higher energy level to a lower one, it emits a photon with energy equal to the difference between the two levels. These emitted photons correspond to specific spectral lines.

Signup and view all the flashcards

What is the Rydberg constant (R)?

A fundamental constant that appears in the formula for calculating the energy of hydrogen's spectral lines.

Signup and view all the flashcards

How does the Bohr model relate to atomic spectra?

The Bohr model predicts the specific frequencies of light that hydrogen emits when its electrons jump between energy levels. These frequencies correspond to the observed spectral lines.

Signup and view all the flashcards

What are the limitations of the Bohr model?

It only applies to hydrogen-like atoms with one electron. It doesn't explain the spectra of multi-electron atoms, spin, or the Heisenberg Uncertainty Principle.

Signup and view all the flashcards

How are photon transitions related to spectral lines?

Each photon emitted during an electron transition between energy levels has a specific frequency. These frequencies correspond to the distinct spectral lines observed in the atomic spectra.

Signup and view all the flashcards

How do you calculate the energy of a photon transition?

Use the formula: EUpper - ELower = hcR(1/nLower^2 - 1/nUpper^2), where 'n' is the principal quantum number, 'R' is the Rydberg constant, and 'h' and 'c' are Planck's constant and the speed of light.

Signup and view all the flashcards

Bohr Model

A model of the atom where electrons orbit the nucleus in specific, quantized energy levels.

Signup and view all the flashcards

Quantized Energy Levels

Electrons can only exist in specific energy states, not anywhere in between.

Signup and view all the flashcards

What determines the energy of a photon?

The energy of a photon is determined by the difference in energy between the two energy levels involved in an electron transition.

Signup and view all the flashcards

What does the Bohr model explain?

The Bohr model successfully explains the line spectrum of hydrogen, which is why it is important.

Signup and view all the flashcards

What does the de Broglie equation describe?

The de Broglie equation relates the momentum of a particle to its wavelength.

Signup and view all the flashcards

Spectral Lines

Distinct colors of light emitted by atoms when electrons transition between energy levels.

Signup and view all the flashcards

Limitations of Bohr Model

The Bohr model only works for simple atoms like hydrogen and cannot explain more complex atoms.

Signup and view all the flashcards

Why is the Rydberg constant important?

It's a fundamental constant used in the Rydberg equation, helping us calculate hydrogen's spectral lines.

Signup and view all the flashcards

How do electron transitions relate to spectral lines?

When an electron jumps between energy levels, it emits or absorbs a photon with a specific energy, resulting in a spectral line.

Signup and view all the flashcards

Study Notes

Bohr Model of the Atom

  • The Bohr model explains the line spectrum of hydrogen.
  • In this model, the electron can only exist in certain, specific orbits.
  • The electron's energy is quantized.
  • The allowed orbits have angular momentum values of nh/2Ï€, where n is an integer.
  • The energy of an electron is related to its orbit number (n).
  • Higher energy level states are excited states.
  • Electrons can transition between energy levels by absorbing or emitting photons.
  • The greater the fall the greater the energy released.

Energy Transitions and Wavelengths

  • Electrons transition between energy levels by emitting or absorbing photons of specific energy and wavelengths.
  • Lyman series: Electromagnetic radiation in the ultraviolet region (n=1)
  • Balmer series: Electromagnetic radiation in the visible and ultraviolet regions (n=2)
  • Paschen series: Electromagnetic radiation in the infrared region (n=3)
  • Brackett series: Electromagnetic radiation in the infrared region (n=4)
  • Pfund series: Electromagnetic radiation in the infrared region (n=5)

Specific Wavelength Values

  • Lyman series: 91.2 nm, 97.3 nm, 102.6 nm, 121.6 nm
  • Balmer series: 364.8 nm, 410.2 nm, 434.1 nm, 486.1 nm, 656.3 nm
  • Paschen series: 820.8 nm

Bohr Model Limitations

  • The model fails to explain the spectra of atoms more complex than hydrogen.
  • The model does not give information on electron distribution within atoms, or relative intensity of spectral lines.
  • It fails to predict the fine structure of spectral lines.
  • The Bohr model doesn't explain selection rules for transition, or the rates of transitions.
  • The model ignores the effects of electric and magnetic fields (Stark and Zeeman effects).

Extensions of the Bohr Model

  • Finite nuclear mass: The nucleus and electron rotate around a common center of mass.
  • Elliptical orbits (Bohr-Sommerfeld model): Electrons can follow elliptical orbits.

Reduced Mass

  • The reduced mass (µ) is used in calculations involving the nucleus-electron system's mass.
  •   The reduced mass is used when calculating isotope shifts, which occur because different isotopes of the same atomic species have differing reduced masses.

Hydrogen-Like Atoms

  • The Bohr model can be applied to any atom with a single electron ( H and singly-ionized Helium).
  • The formula must be modified for other atoms with more than one electron, because quantum mechanics is necessary if you want to describe multielectron systems.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

CHE1112 Lecture I-part II PDF

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser