9. Quantum Mechanics

Emission Spectrum

Absorption and Emission Spectra

 (A) The element has three stable isotopes. 

 There are other statements that are true as well. 

 (B) The isotope with a mass of 27 is the most abundant. 

 (C) The atomic mass of the element will be very close to 27. 

 While this is the largest peak, recall that atomic mass is a weighted average. 

 (D) The most abundant isotope has a mass of 25. 

 Recall that the larger the peak the greater the abundance. 

 Correct. The element has three stable isotopes, and the isotope with a mass of 27 is the most abundant. 

 There is at least one statement that is not correct. 

 Recall that each of the mass peaks represents the mass of a given isotope and the intensity is related to their abundance. 

Consider the mass spectrum for a hypothetical element given below. <img src="https://media.pearsoncmg.com/ph/esm/esm_tro_chemistry_6/msa/content/practice-quiz/img/troama5_pq_c2q20.jpg" ALT="Mass spectrum (bar graph) showing %Intensity versus Mass (amu). The graph has three bars at masses 25, 26, and 27 with intensity percents, respectively, of 90%, 80%, and 100%." class="block">Which of the following statements correctly relates to this spectrum?

Emission and Absorption Line Spectra - A Level Physics

 Higher energy levels are more closely spaced than lower levels. 

Correct this transition emits the same amount of energy that is absorbed when n = 2 &#8594; n = 5 occurs.

Use the equation that relates n and the difference in energy between the stationary states to calculate the energy and then compare.

 Which of the following transitions results in the emission of the highest-energy photon? 

Spectroscopy is a technique that uses the interaction of radiant energy with matter to identify or quantify a substance in a sample. A deuterium lamp is often used a light source in the ultraviolet region of the spectrum and the emission spectrum is shown. Is this a continuous or line emission spectrum?
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/61c5e5bd8c3cd7c6-1669906169179.jpg" alt="" />

 Calculate the energy between the two states and then convert to wavelength using appropriate equations. 

Use the equation that relates n and the difference in energy between the stationary states to calculate the energy and then convert to the corresponding wavelength.

When an electron in a hydrogen atom moves from n = 8 to n = 2, light with what wavelength is emitted?

Types of Spectra -  Emission and Absorption Spectra

When a copper salt such as Cu(NO3)2 is burned in a flame, a blue-green color is emitted. Which figure represents the emission spectrum for the element copper? (LO 5.6)?
(a) <img src="" alt="" />
(b) <img src="" alt="" />
(c) <img src="" alt="" />
(d) <img src="" alt="" />

Emission Spectrum Example 1

A certain quantum-mechanical system has the energy levels
shown in the accompanying diagram. The energy levels are
indexed by a single quantum number n that is an integer.
(a) As drawn, which quantum numbers are involved in the
transition that requires the most energy? (b) Which quantum
numbers are involved in the transition that requires the
least energy? (c) Based on the drawing, put the following in
order of increasing wavelength of the light absorbed during
the transition: (i) n = 1 to n = 2; (ii) n = 2 to n = 3; (iii)
n = 2 to n = 4; (iv) n = 1 to n = 3.

A certain quantum-mechanical system has the energy levels 
shown in the accompanying diagram. The energy levels are 
indexed by a single quantum number n that is an integer. 
(b) Which quantum 
numbers are involved in the transition that requires the 
least energy?<img src="https://lightcat-files.s3.amazonaws.com/problem_images/38d4e7b0b001e8a3-1660754041696.jpg" alt="" />

According to the quantum-mechanical model for the hydrogen 
atom, which electron transition produces light with the longer 
wavelength: 3p¡2s or 4p¡3p ?

The Lyman series of emission lines of the hydrogen atom are
those for which nf = 1. (a) Determine the region of the electromagnetic
spectrum in which the lines of the Lyman series
are observed.

The series of emission lines of the hydrogen atom for which 
nf = 4 is called the Brackett series. (a) Determine the region 
of the electromagnetic spectrum in which the lines of the 
Brackett series are observed.

The visible emission lines observed by Balmer all involved
nf = 2. (a) Which of the following is the best explanation of
why the lines with nf = 3 are not observed in the visible portion
of the spectrum: (i) Transitions to nf = 3 are not allowed
to happen, (ii) transitions to nf = 3 emit photons in the
infrared portion of the spectrum, (iii) transitions to nf = 3
emit photons in the ultraviolet portion of the spectrum, or
(iv) transitions to nf = 3 emit photons that are at exactly the
same wavelengths as those to nf = 2.

Emission Spectra and the Bohr Model

Sodium-vapor lamps are a common source of lighting. The emission spectrum from this type of lamp is shown. Is this a continuous or line emission spectrum?
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/831e721feaa2c45f-1669908991942.jpg" alt="" />

 This is the energy of a photon in mJ/photon that must be used in the calculation. 

 This is the energy of a photon (J/photon) that must be used in the calculation. 

 Correct calculation and unit conversion. 

 Compare the energy of a single photon to the energy of the pulse. 

 The units of the pulse and the photon should have the same unit of joules and the wavelength should be converted to meters. 

Epulse/Ephoton = number of electrons

 How many photons of light are emitted in a 4.50-mJ pulse of a laser with a wavelength of 555 nm? 

Emission and Absorption Spectra

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1. Intro to General Chemistry

2. Atoms & Elements

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

7. Gases

8. Thermochemistry

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

Wavelength and Frequency

Wavelength&nbsp;is the distance from one crest of a wave to another, whereas frequency is the number of waves within a second.&nbsp;

Quantum Numbers: Spin Quantum Number

The Spin Quantum Number deals with the spin of an electron within an orbital.

Speed of Light

The Speed of Light in a vacuum is related to the wavelength and frequency of a light particle.

Bohr Equation

In the Bohr Equation, the energy and wavelength a photon is related to its energy shell transitions.

Quantum Numbers: Angular Momentum Quantum Number

The&nbsp;Angular Momentum Quantum Number&nbsp;gives the shape of the atomic orbitals.

Emission Spectra is a series of lines formed when emitted light is focused by a slit and passed through a prism. &nbsp;

Introduction to Quantum Mechanics

The 4 Quantum Numbers provide us the coordinates to find the theoretical location of an electron.

Quantum Numbers: Nodes

A node is the region in an atom with zero electron density and where an electron is least likely to exist.

The Energy of Light

The Energy of Light&nbsp;involves the use of a new variable Planck's Constant.

Electromagnetic Spectrum

The Electromagnetic Spectrum is the different forms of radioactive energy that exists in our universe.

Heisenberg Uncertainty Principle

Heisenberg's Uncertainty Principle&nbsp;tries to explain the potential duality of an electron behaving as either a particle or wave.&nbsp;

Quantum Numbers: Number of Electrons

The Quantum Numbers can give both the quantity and location of electrons within a given atom.&nbsp;

Quantum Numbers: Principal Quantum Number

The Principal Quantum Number gives both the size and energy of an electron shell.&nbsp;

Photoelectric Effect

What happens when light strikes the surface of a metal? The Photoelectric Effect&nbsp;can help to explain that.&nbsp;

Quantum Numbers: Magnetic Quantum Number

The Magnetic Quantum Number gives the location of an electron within a specific orbital.

Bohr Model

In the Bohr Model, electrons can move up and down to different orbitals or shells based on absorbing or releasing of energy.&nbsp;

De Broglie Wavelength

The&nbsp;De Broglie Wavelength equation relates wavelength to velocity or speed.&nbsp;