Physics Chapter on Light and Electromagnetic Waves

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Questions and Answers

What is the electronic configuration of fluorine?

1s2 2s2 2p5 (correct)

1s2 2s2 2p4

1s2 2s2 2p6

1s2 2s2 2p3

Which rule states that electrons must occupy separate orbitals before pairing up?

Heisenberg uncertainty principle

Aufbau principle

Pauli exclusion principle

Hund's rule (correct)

How many electrons are present in neon?

10 (correct)

What is the correct quantum notation for the configuration of nitrogen?

1s2 2s2 2p3 Signup and view all the answers

Which element completes the second energy level and has a stable octet?

Neon Signup and view all the answers

What does each line in an atomic emission spectrum represent?

An exact wavelength of emitted light Signup and view all the answers

Which of the following best describes the role of a spectroscope?

To separate emitted light into line spectra Signup and view all the answers

What is the principal quantum level indicated by the number '4'?

The fourth main energy level Signup and view all the answers

Which of the following correctly states the relationship between principal energy levels and sublevels?

The number of sublevels in each main energy level equals the level number Signup and view all the answers

What happens to electrons when they return to the ground state from an excited state?

They emit a characteristic color of light Signup and view all the answers

What shape does the p sublevel have in atomic orbitals?

Dumbbell shape Signup and view all the answers

What is the maximum number of electrons that can occupy a single orbital?

2 electrons Signup and view all the answers

How many total orbitals are there in the d sublevel?

5 orbitals Signup and view all the answers

What phenomenon did Thomas Young's experiment with light slits demonstrate?

Light can produce interference patterns. Signup and view all the answers

What is the fundamental concept that connects particles and waves in physics?

Wave-particle duality Signup and view all the answers

What is the expression that relates the speed, wavelength, and frequency of light?

$c = \lambda f$ Signup and view all the answers

In the context of electromagnetic radiation, which of the following is NOT a form of light energy?

Sound waves Signup and view all the answers

Which type of electromagnetic radiation has the shortest wavelength?

X-rays Signup and view all the answers

Which statement correctly describes how the frequency and wavelength of electromagnetic waves relate mathematically?

Frequency is inversely proportional to wavelength. Signup and view all the answers

What is the frequency of light with a wavelength of 4.257 x 10-9 cm?

7.0 x 10^16 Hz Signup and view all the answers

Which aspect of light is indicated by the amplitude of a wave?

The energy transported by the wave Signup and view all the answers

How is the energy of a photon related to its frequency?

E is directly proportional to frequency Signup and view all the answers

What characterizes the ground state of an atom?

Electrons occupy the lowest available orbitals Signup and view all the answers

When discussing the electromagnetic spectrum, which of the following statements is true?

The electromagnetic spectrum includes a range of wavelengths and frequencies. Signup and view all the answers

What happens to an electron when it absorbs energy?

It jumps to a higher energy level Signup and view all the answers

Which of the following formulas predicts the emission lines of hydrogen?

Rydberg formula Signup and view all the answers

What does Planck's constant represent in the energy equation E = hv?

The proportionality constant Signup and view all the answers

What results from an electron transitioning from an excited state back to the ground state?

It emits light Signup and view all the answers

Which principle states that a particle's position and velocity cannot both be precisely determined at the same time?

Heisenberg Uncertainty Principle Signup and view all the answers

What principle states that no more than two electrons can occupy the same orbital?

Pauli Exclusion principle Signup and view all the answers

Which of the following configurations represents lithium?

1s22s1 Signup and view all the answers

Which filling order is correct according to the Aufbau principle?

1s, 2s, 2p, 3s Signup and view all the answers

In the electron configuration for carbon, how many electrons occupy the p orbital?

2 Signup and view all the answers

What is the maximum number of electrons that can occupy the 4d orbital?

10 Signup and view all the answers

Under what condition do two electrons in the same orbital exhibit according to the Pauli Exclusion principle?

Must have opposite spins Signup and view all the answers

Which electron configuration is characteristic of beryllium?

1s22s2 Signup and view all the answers

What term describes the filling of electrons in the lowest available energy levels first?

Aufbau principle Signup and view all the answers

What is the electron configuration for phosphorus?

1s22s22p63s23p3 Signup and view all the answers

Which element has the electron configuration of 1s22s22p63s23p6?

Argon Signup and view all the answers

Which element's configuration is characterized by the orbital notation 2-8-1?

Sodium Signup and view all the answers

What is the orbital notation for magnesium?

2-8-2 Signup and view all the answers

What does the principal quantum number 'n' indicate?

Energy level of the electron Signup and view all the answers

How many total electrons does sulfur have?

16 Signup and view all the answers

Which element possesses the configuration 1s22s22p63s23p5?

Chlorine Signup and view all the answers

What is the unique feature of iron's configuration compared to other elements in period #4?

It includes the 3d subshell filled with electrons. Signup and view all the answers

What shape does the 'l' quantum number represent for d orbitals?

double dumbbell Signup and view all the answers

Which quantum number relates to the orientation of an electron cloud?

Magnetic quantum number Signup and view all the answers

Study Notes

Light

Light, in the 19th century, was shown to exhibit wave-like behavior. Thomas Young's experiments demonstrated interference patterns.
Newtonian particle models couldn't explain this, but wave models could.
James Clerk Maxwell further demonstrated light as part of a spectrum of electromagnetic waves.
Particles and waves are connected on a fundamental duality level.
A wave is an oscillation or periodic movement, transporting energy through space (example: a rope or pebble in a pond).

Properties of Light

Electromagnetic radiation is a form of energy exhibiting wave-like behavior. Examples include X-rays, UV, infrared, microwaves, and radio waves. These together form the electromagnetic spectrum.
Light moves at a constant speed (c), 3.0 x 10⁸ m/s.

Properties of Light (Continued)

Wavelength (λ): Distance between corresponding points on adjacent waves. Measured in meters.
Frequency (ν): Number of waves passing a given point per second, measured in Hertz (Hz).
Speed, Frequency & Wavelength are related: c = λν

Properties of Waves

Wavelength (λ): Distance from crest to crest.
Speed of light (c): 300,000 km/sec (rate of motion of crests or troughs).
Period (T): Time between passage of successive crests.
Frequency (ν): Number of crest passages per unit time.
Amplitude (A): Distance from level of crest to level of trough.

Relationship between wavelength, frequency and speed

One dimensional sinusoidal waves showing the relationship among wavelength, frequency, and speed.
The wave with the shortest wavelength has the highest frequency.
Amplitude is half the height of the wave from peak to trough.

Electromagnetic Spectrum

The electromagnetic spectrum is the range of all types of electromagnetic radiation.
Visible light is a small portion.
Visible light colors have specific frequencies and wavelengths.

Wave Mechanics

Wavelength: Distance between peaks, measured in nanometers (nm).
Frequency: Number of peaks passing a point per second, measured in Hertz (Hz).
The speed of radiation (c) is determined by: c = λν (speed = wavelength x frequency).

Problems using the Speed Equation

Example: Calculate the frequency of light with a wavelength of 4.257 x 10⁻⁹ cm, given the speed of light is 3.0 x 10⁸ m/s.
To solve, convert cm to m, substitute values for speed (c) and wavelength ( λ), and then solve for frequency (ν): V = c/λ
Result: Frequency ≅ 7.0 x 10¹⁶ Hz

Relationship of Energy and Frequency

The relationship between energy (E) and frequency (ν) of a photon is: E = hν, where h is Planck's constant (6.626 x 10⁻³⁴ J•s).
Example: Calculate the energy of a photon with a frequency of 4.50 x 10¹⁴ Hz. Energy (E)=hν= 2.98 x 10⁻¹⁹ J

Planck and Einstein

Planck developed a theoretical expression for blackbody radiation, an ideal emitter.
Planck's Constant: h = 6.626 x 10⁻³⁴ J•s.
Einstein's equation: E = mc²

More Contributors and Concepts

Balmer (Balmer Series): Empirical equation for hydrogen line spectrum.
Rydberg: Empirical formula predicting hydrogen emission lines.
Rydberg Constant: 1.097 x 10⁷ m⁻¹.
De Broglie: Wavelength associated with particles, not just waves.
Heisenberg Uncertainty Principle and Schrödinger's Equation: Birth of quantum mechanics.

Electron Configuration (Ground State vs. Excited State)

Ground state: All electrons in lowest available orbitals.
Excited state: Electrons absorb energy and jump to higher energy levels. (Absorption)
Electrons fall back to the ground state, releasing energy as visible light. (Emission)

Absorption

When an electron "jumps" to a higher energy level, it absorbs energy.
The excited state is a temporary state.

Emission

The electron falls back to the ground state, emitting energy in the form of light.
Each element has a unique spectrum (think about a prism).

Light and Atomic Spectra (bright line spectra)

Atomic emission spectra produce narrow lines of color called bright line spectra.
Each line corresponds to an exact wavelength.
The electromagnetic spectrum shows wavelength in meters, frequencies in Hz, and a portion of the spectrum showing wavelengths in nanometers, and colors.

Experiments (Flame Tests)

Demonstrates the emission spectrum of a substance.
Elements heated to high temperatures enter the excited state.
Characteristic emitted color occurs when electrons return to the ground state. This is used to determine metal ion presence in a substance.

Experiments (Spectroscopy)

Spectroscopy is used for viewing bright line spectra of gases.
Performed by viewing a gas tube through which an electric current passes.
A spectroscope (using a prism) separates emitted light into line spectra.

Quantum Theory

Developed to explain atomic chemical behavior.
Quantum numbers describe electron location in an atom.
Quantum: Minimum quantity of energy lost or gained by an atom.

Electrons

Found in orbitals, three-dimensional regions around the nucleus.
Orbitals indicate probable electron location.
Chemical properties are based on the number of outer energy levels.

Electrons (Continued)

Electrons occupy the lowest sublevel possible.
Sublevels are orbitals with different shapes (s, p, d, f).

The Quantum Model of the Atom

The study of emission spectra of elements leads to the development of principal quantum level and the model of electron arrangement.
Three levels are: 1. principal quantum level (n), 2. sublevel (s, p, d, f), 3. orbital (s=1, p=3, d=5, f=7).

Rules of Occupancy

Seven main energy levels.
Number of sublevels = the principle quantum number (e.g., n=3 has 3 sublevels).
Number of orbitals per sublevel: s=1, p=3, d=5, f=7.
Two electrons per orbital.
Maximum electrons per main energy level = 2n².

Putting it Together

"n" describes the orbital size and principle energy level of the shell..
There are n² orbitals per shell.
Size of the orbital increases as n increases, and electrons are further away from the nucleus.

Electron Configurations and Periodic Table

The table orders elements by similar physical and chemical properties.
Groups have similar valence electron configurations.
Valence electrons are those of the highest principle energy level (highest n value).
These are important for chemical reactions.
Example: Gallium (Ga) [Ar]4s²3d¹⁰4p¹
The completely filled 3d orbitals count as core, not valence electrons.

Transition Elements

Metals in which the last electron added is in a d orbital.
Valence electrons : ns and (n-1)d electrons.
Example: Vanadium (V) [Ar] 4s²3d³

Inner Transition Elements

Metals in which the last electron added is in an f orbital.
Valence electrons: ns,(n-2)f , and if present (n-1) d electrons.
Example: Promethium (Pm) [Ar] 6s²4f⁵

Electron Configurations of Ions

Ions are formed when atoms gain or lose electrons.
Cations (positive ions) have electrons removed. Main group elements lose the externally added electrons first, transition metals lose ns electrons first then (n-1) d.
Anions (negative ions) have electrons added. Added according to the Aufbau principle.

Predicting Electron Configurations of Ions

Example calculation to determine electronic configurations of ions.

Summary

The above study notes explain the periodicity observed in the periodic table, which is due to patterns in electron configurations.

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Description

This quiz covers the fundamental properties and behaviors of light as explored in the 19th century. It includes topics such as wave-particle duality, the electromagnetic spectrum, and the measurements of wavelength and frequency. Test your understanding of these concepts related to light and electromagnetic radiation.