Electromagnetism and Atomic Structure: A Comprehensive Guide

Classified in Chemistry

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  • Isotopes

    • Same elements with different numbers of neutrons

  • Ions

    • Same element with an unequal number of protons and electrons

  • Electric Fields

    Things with charge (protons and electrons) generate electric fields (E) (Likewise, electric fields can affect things with charge)

  • Energy and Matter

    When atoms or molecules “happen across” energy, [usually] 1 of 2 things can happen: 1) they wiggle-jiggle more [we classify the amount of “wiggling-jiggling” by the quantity of temperature] 2) the energy, if it is a) in the form of a special type of electromagnetic field and b) of a specific frequency, can be absorbed

    λ∙f = c

    λ = wavelength of the wave [m]

    f = frequency of the wave [Hertz, Hz=1/s]

    c = speed of light = 3∙108 m/s

    Electromagnetic Waves can also be thought of as [massless] Electromagnetic Particles [a.k.a., Photons]

    E = h∙f = h∙c/λ

    E = energy of the wave [J]

    h = Planck’s constant = 6.626∙10-34 J∙s

    "All things glow" means everything is producing EM and therefore energy and heat

    Wien's Law: λmax∙T=0.0029 [m∙K]

    λmax = wavelength of maximum energy emission

    T = temperature of the object

    Stefan's Law: P = E/Δt =ε∙σ∙A∙T4( as T goes up, total E emitted goes up)

    ε = object’s emissivity (ranges from 0 to 1)

    σ = the Stefan-Boltzmann constant

    A = the objects surface area

    T = temperature of the object

  • Black Body

    • Constant temp

    • Uniform composition

    • Exactly distributed

    • Lots of atoms

    • Not real

    • Conversely, all normal matter absorbs electromagnetic radiation to some degree. An object that absorbs all radiation falling on it, at all wavelengths, is called a black body. When a black body is at a uniform temperature, its emission has a characteristic frequency distribution that depends on the temperature.

  • Subatomic Particles

    • Proton

      • Positive charge

      • +

    • Neutron

      • No charge

      • n

    • Electron

      • Negative charge

      • e-

  • Radioactive Decay

    • Alpha Particles

      Are released by high mass, proton-rich unstable nuclei. The alpha particle is a helium nucleus; it consists of two protons and two neutrons. It contains no electrons to balance the two positively charged protons. Alpha particles are therefore positively charged particles moving at high speeds.

    • Beta Particles

      Are emitted by neutron-rich unstable nuclei. Beta particles are high energy electrons. These electrons are not electrons from the electron shells around the nucleus but are generated when a neutron in the nucleus splits to form a proton and an accompanying electron. Beta particles are negatively charged.

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