ATOMIC STRUCTURE in 60 Minutes || Full Chapter Revision || Class 11th JEE

JEE Wallah・2 minutes read

Subatomic particles were discovered in a gas at low pressure. The discovery of electrons, protons, and neutrons was detailed, along with key formulas for understanding the electromagnetic spectrum and atomic models.

Insights

  • Subatomic particles like electrons, protons, and neutrons were discovered through various experiments, leading to the development of atomic models that highlighted the nucleus and electron orbits, with key formulas emphasizing the importance of understanding the electromagnetic spectrum and properties like wavelength, frequency, and velocity.
  • Quantum theory and principles like the Heisenberg Uncertainty Principle and the concept of orbitals in quantum mechanical models provide insights into the behavior of electrons within atoms, including quantum numbers determining energy levels and electron locations, as well as rules governing electron spin and distribution within subshells based on atomic number, showcasing the intricate organization and stability of electron configurations in atoms.

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Recent questions

  • What are subatomic particles?

    Tiny particles within atoms.

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Summary

00:00

Discovery of Subatomic Particles in Gas

  • Subatomic particles were discovered in a gas at low pressure.
  • Thomson's atomic model highlighted the non-uniform distribution of charges.
  • Magnetic nature and radiation properties were discussed.
  • Formulas related to subatomic particles were emphasized.
  • Discovery of electrons, protons, and neutrons was detailed.
  • Thomson discovered electrons using a discharge tube experiment.
  • Protons were discovered through the Gold Foil Experiment by Rutherford.
  • Neutrons were discovered through alpha particle bombardment on beryllium.
  • Rutherford's atomic model focused on the nucleus and electron orbits.
  • Isoelectronic species, isotopes, and isobars were explained.

13:53

Understanding Electromagnetic Spectrum: Key Concepts Explained

  • Date of arrangement today; understanding the electromagnetic spectrum is crucial.
  • Wavelength is the primary factor, denoted by Lambda.
  • Radiation exhibits maxima and minima distances, with Lambda representing the distance.
  • Frequency is the number of cycles completed in one second.
  • Velocity is the distance traveled in unit time.
  • Key formula: Frequency = 1 / time (t).
  • Quantum theory explains energy absorption in packets.
  • Photon is the smallest energy packet in light, proportional to frequency.
  • Photoelectric effect involves ejecting electrons from a metal surface with light.
  • Spectrum analysis reveals emission and absorption lines, distinguishing continuous and discontinuous spectra.

28:30

Hydrogen Atom Energy Levels and Formulas

  • The Balmer series in the visible region is followed by the saree series in the import region.
  • The formula to find the wavelength number of radiation produced by a hydrogen atom is given by R = 1096 doubles constant * (1 / n1² - 1 / n2²).
  • The value of n1 is lower and n2 is higher, representing different energy levels.
  • For the Balmer series, n1 is always 2, while for the Lemon series, n1 is always 1.
  • The Rutherford Atomic Model states that the energy of an electron remains constant unless it changes energy states.
  • Angular momentum in the atomic model is represented by MBR, with n being an integral multiple.
  • The formula for the radius of an electron's orbit is 0.529 * n² / Z.
  • The formula for the velocity of an electron is given, along with the formula for its energy in different energy states.
  • The Broglie wavelength formula lambda = h / √2mke is used to calculate the wavelength associated with microscopic particles.
  • The Heisenberg Uncertainty Principle states that the position and momentum of microscopic particles cannot be measured with absolute accuracy simultaneously.

43:09

"Quantum Numbers: Electron Location and Spin"

  • The space inside an atom with the highest probability of finding an electron is called an orbital.
  • Quantum mechanical models rely on quantum numbers to provide information about the electron's location.
  • The principal quantum number, denoted by small n, determines the electron's energy level and cell location.
  • The principal quantum number indicates the electron's position in a cell, with a value of one representing the first cell.
  • The energy of an electron increases as the principal quantum number moves farther from the nucleus.
  • Each cell can hold a maximum of 12 electrons, with the number of orbitals being n².
  • The azimuthal quantum number, denoted by L, determines the subshell in which the electron is present.
  • The magnetic quantum number, denoted by M, indicates the orientation of the electron within a subshell.
  • The spin quantum number, denoted by S, determines the spin of an electron, with possible values of plus or minus half.
  • Electrons in an orbital must have opposite spins, and the exclusion principle states that no two electrons in an orbital can have the same set of quantum numbers.

56:24

"Electron Configuration and Orbital Angular Momentum"

  • Electrons must be filed in specific subshells according to the atomic number of an element; for example, sodium with an atomic number of 11 requires two electrons in 2s, two in 2p, six in 3s, and one in 3p.
  • The formula for Orbital Angular Momentum is √(l(l+1))h/2π, where l represents the azimuthal quantum number; this formula is crucial for understanding electron configurations and stability.
  • Electron configurations for elements like chromium and copper may deviate from the expected order due to the stability gained from half-filled or fully-filled orbitals, such as in the case of copper with an atomic number of 29 having an electronic configuration of 4s1 3d10 instead of 4s2 3d9, showcasing the significance of electron exchange energy in stability.
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