Basin

• What has accumulated over the past 200 years to support the atomic model?

  A great deal of experimental evidence
• What happened when the atomic theory proved to be scientifically and philosophically untenable?

  More experiments were engaged by great philosophers
• Who advanced the atomic concept around 400 BC?

  Democritus and Leucippus
• What was the role of accurate measurements in the experiments conducted by philosophers?

  They provided quantitative scientific data
• What did Mendeleev and other atomic scientists assemble based on years of work?

  The three fundamental laws of atomic theory
• What does Dalton's theory fail to explain?

  Many naturally occurring phenomena such as electrical conductivity and emission spectra
• What was one of the difficult aspects regarding the periodic table mentioned in the text?

  How to handle the periodic table for displaying light
• What confusion arose from the discovery of electrons, protons, and neutrons?

  How to organize data in the periodic table
• What does the periodicity of properties of atoms account for?

  The periodicity of the properties of elements in a column structure
• What did Dalton's theory get replaced by?

  The laws of chemical physics
• What did Planck discover about energy emitted or absorbed by atoms?

  It consists of discrete packets called quanta
• What is the formula to calculate the energy of a quantum?

  E = hν
• What is Planck's constant?

  1. 63×10⁻³⁴ J⋅s
• What did Planck's discovery explain regarding classical physics?

  The ultraviolet catastrophe
• What is the relationship between electromagnetic radiation and photons according to Einstein?

  Electromagnetic radiation exists as packets of energy called photons
• What happens when a photon has too low frequency in the photoelectric effect?

  It produces fewer electrons
• What is the equation to determine the threshold frequency in the photoelectric effect?

  v₀ = E/Φ
• What does the equation \(c = \lambda \nu\) represent?

  The relationship between the speed of light, wavelength, and frequency
• What is the speed of light in meters per second?

  1. 998 x 10⁸ m/s
• How are wavelength and frequency related?

  They are inversely proportional
• If the wavelength of light is 650 nm, what is its frequency?

  $4.62 \times 10^{14} \text{s}^{-1}$
• What is the energy of a photon with a frequency of $6.51 \times 10^{14} \text{s}^{-1}$?


  $4.32 \times 10^{-19} \text{J}$
• What are the primary characteristics of electromagnetic radiation?

  • Wavelength
  • Frequency
  • Speed of light
• What are the types of electromagnetic radiation?

  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
  • Gamma rays
• What is the significance of electromagnetic radiation in energy exchange?

  • Carries energy in transmitted waves
  • Energy increases through collisions with molecules
  • Causes emission of other radiation
• What is the relationship between energy and wavelength in electromagnetic radiation?

  • Energy is inversely proportional to wavelength
  • Shorter wavelengths have higher energy
  • Longer wavelengths have lower energy
• What is the role of cathode rays in the understanding of matter?

  • Streams of electrons that carry energy
  • Led to discoveries affecting perceptions of matter
  • Showed that matter is more complex than just atoms
• What is the concept of quantized energy levels?

  • Energy emitted or absorbed by atoms is in discrete packets
  • Established by Planck's discovery
  • Fundamental to quantum theory
• What is the photoelectric effect?

  • Emission of electrons from a material when exposed to light
  • Depends on the frequency of the incident light
  • Threshold frequency determines electron emission
• What is the significance of Einstein's proposal regarding electromagnetic radiation?

  • Proposed that electromagnetic radiation is quantized
  • Introduced the concept of photons
  • Changed the understanding of light and energy
• What is the relationship between frequency and energy in the context of photons?

  • Energy is directly proportional to frequency
  • Higher frequency means higher energy
  • Lower frequency means lower energy
• What is the significance of the threshold frequency in the photoelectric effect?

  • Determines the minimum frequency needed to emit electrons
  • Below this frequency, no electrons are emitted
  • Related to the work function of the material