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Structure of Atoms in One Shot - JEE/NEET/Class 11th Boards || Victory Batch

PW English Medium・2 minutes read

The text provides a detailed overview of the discovery of fundamental atomic particles, their properties, and electron configurations, culminating in explanations of quantum numbers and electronic configurations. It emphasizes the importance of positive thinking, stability through electronic configurations, and the mindset of overcoming challenges for success.

Insights

Dalton's atomic theory proposed atoms as the smallest indivisible particles, laying the foundation for modern atomic structure understanding.
J.J. Thomson's experiments with cathode rays led to the discovery of electrons, revealing their negative charge and specific charge independent of gas nature.
Millikan's oil drop experiment determined the electron's mass, showcasing its minuscule size compared to a hydrogen atom.
Goldstein's discovery of protons as positively charged particles with a mass akin to hydrogen emphasized the fundamental nature of these particles.
Chadwick's identification of neutrons as neutral particles with a mass similar to protons further enriched the understanding of atomic composition.
Bohr's model introduced the concept of quantized electron orbits, providing insights into energy levels, radii, and total energies within atoms.
The rules governing electron configuration, such as Pauli's exclusion principle and Hund's rule, dictate the filling of orbitals to achieve stability and maximize multiplicity.

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Recent questions

What are the fundamental particles of an atom?
Electrons, protons, neutrons.

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Summary

00:00

"Atomic Theory: Discovery of Cathode Rays"

Introduction to the physics platform, transitioning from chemistry to the structure of atoms.
Explanation of Dalton's atomic theory stating atom as the smallest indivisible particle.
Introduction to the three fundamental particles: electrons, protons, and neutrons.
Discovery of electrons through the study of cathode rays by William Crookes.
Experiment setup with a Crookes tube, electrodes, and high voltage for electricity conduction.
Observations during the experiment with varying pressures and voltages.
Properties of cathode rays: travel in a straight line, made up of material particles, carry negative charge, and deflect in electric and magnetic fields.
Effects of cathode rays: heating effect, ionization of gases, production of x-rays, impact on photographic plates, and penetrating effect.
Explanation of charge to mass ratio experiments by J.J. Thomson with electric and magnetic fields.
Specific charge of electrons found to be independent of the nature of gas, with a value of 1.76 x 10^8 coulombs per gram.

19:15

"Charge and Mass of Fundamental Particles"

Deviation of cathode rays depends on three factors: negative charge magnitude, particle mass, and magnetic field strength.
Electric field causes deviation towards path A, magnetic field towards path C, and no field or equivalent fields towards path B.
J.J. Thomson's experiment revealed the electron's charge as -1.6 x 10^-19 coulombs.
Millikan's oil drop experiment determined the electron's mass as 9.11 x 10^-28 grams, 1/1837th of hydrogen's mass.
Oil droplets in the experiment were ionized by x-rays, surrounded by electrons, leading to charge calculations.
Applying electric field accelerated or stopped oil droplets' motion, with the smallest charge found being -1.6 x 10^-19 coulombs.
Charge on oil droplets is an integral multiple of the electron's charge.
Protons, discovered by Goldstein, are positively charged particles with a mass equal to that of a hydrogen atom.
Protons travel in straight lines, produce heating effects, and are deflected by magnetic fields.
Proton's charge is +1.6 x 10^-19 coulombs, and its mass is 1.6 x 10^-24 kg, defining it as a fundamental particle with positive charge and mass similar to hydrogen.

36:25

"Atomic Structure: Protons, Neutrons, Electrons, Success"

Positive thinking is crucial for success in exams, likened to thinking like a proton, which is always positive.
The discovery of the neutron by Chadwick involved bombarding beryllium with alpha particles, resulting in the production of neutrons.
Neutrons are neutral particles with a mass similar to that of a proton, making them fundamental particles.
Definitions of electrons, protons, and neutrons: electrons have a negative charge and a mass equal to 1/1837 of a hydrogen atom, protons have a positive charge and a mass equal to that of a hydrogen atom.
Thompson's atomic model compared atoms to a watermelon, with positively charged species containing embedded electrons, leading to the conclusion that atoms are neutral.
Rutherford's scattering experiment with alpha particles on gold foil revealed that atoms have empty space, a positively charged center (nucleus), and a heavy particle in the nucleus.
Observations from Rutherford's model: atoms have empty space, a positively charged nucleus, and a heavy nucleus.
Atoms consist of a nucleus (positively charged, comprising neutrons and protons) and an extra-nuclear part (containing electrons).
Atomic number (Z) represents the number of protons in an atom, while mass number (A) is the sum of protons and neutrons.
In neutral cases, the number of protons equals the number of electrons, ensuring the atom's neutrality.

58:30

Carbon: Atomic Structure and Isotopes

Carbon is represented by the letter C in the periodic table.
The atomic number of carbon is 6, and its mass number is 12.
The number of protons in a carbon atom is 6, which is equal to its atomic number.
The number of neutrons in a carbon atom can be calculated using the formula: mass number = number of neutrons + number of protons.
In the case of carbon, the number of neutrons is also 6.
The number of electrons in a neutral carbon atom is equal to the number of protons, which is 6.
To calculate the number of electrons, protons, and neutrons in a sulfate ion (SO4 2-), you need to consider the atomic numbers and mass numbers of sulfur and oxygen.
The sulfate ion contains 48 protons, 48 neutrons, and 50 electrons.
For a phosphate ion (PO4 3-), the number of protons, neutrons, and electrons for phosphorus and oxygen atoms need to be calculated individually before adding them together.
The phosphate ion contains 47 protons, 48 neutrons, and 50 electrons.
Isotopes are atoms of the same element with the same atomic number but different mass numbers, such as the isotopes of hydrogen (protium, deuterium, tritium).
Isobars are atoms of different elements with the same mass number but different atomic numbers, like argon, potassium, and calcium.
Isotones are atoms in which the elements have the same number of neutrons, such as carbon and nitrogen.

01:14:16

Atomic Numbers, Isotopes, and Quantum Theory

Atomic number of nitrogen is 7, carbon's mass number is 12, and nitrogen's mass number is 15.
Neutrons can be calculated by subtracting atomic number from mass number, resulting in the same number for both carbon-14 and nitrogen-15.
Isotopes like carbon-14 and nitrogen-15 have the same number of neutrons due to their similar atomic numbers.
Isoelectronic species, such as Na+, Mg+2, and Al+3, contain the same number of electrons.
Calculations for mass number, atomic number, protons, electrons, and neutrons are essential for elements like oxygen, sodium ion, and bromine.
For oxygen, the mass number is 16, with 8 protons and electrons each.
Sodium ion has 11 protons, 12 neutrons, and 10 electrons due to its positive charge.
Bromine, as a neutral species, has 35 protons, electrons, and an atomic number.
Light exhibits dual nature - wave and particle - with electromagnetic waves having perpendicular electric and magnetic components.
Planck's theory explains quantization, where energy is emitted in small packets called quanta, like photons, with energy proportional to frequency.

01:32:47

Bohr Model and Spectra Analysis Summary

Spectra analysis involves observing energy levels where electrons move between levels, requiring and releasing energy, leading to spectral lines.
Bohr's model of the atom states that orbits with integral angular momentum multiples of h/2π are allowed for electrons moving between energy levels.
The Bohr model provides information on radius, velocity, and total energy, with the formula for radius being 0.529 * n^2 / z for single-electron species.
For different shells in the same element, the relationship between their radii is expressed as r1/r2 = n1/n2^2.
When considering different elements, the radius relationship formula becomes r1/r2 = n1^2/n2^2 * z2/z1.
The velocity of a moving electron in the Bohr model is given by 2.19 * 10^8 * z/n cm/s.
The total energy formula in the Bohr model is -13.6 * z^2 / n^2 eV/atom, with kinetic energy being the negative of total energy.
Establishing relationships for total energy between different shells in the same element is expressed as e1/e2 = n2/n1^2.
For different elements, the total energy relationship formula is e1/e2 = z1/z2 * n2/n1^2.
The photoelectric effect involves incident photons on a metal surface, releasing electrons based on the work function and resulting in kinetic energy, with the formula hν = hν0 + kinetic energy.

01:50:08

Electron Energy Levels and Spectral Series

Electrons moving from n=1 to n=8 transition between energy levels.
Electrons returning to their original levels create Lyman, Balmer, Paschen, Bracket, Pfund, and Humphrey series.
Lyman series involves electrons returning to n=1 in the ultraviolet region.
Balmer series involves electrons returning to n=2 in the visible region.
Paschen series involves electrons returning to n=3 in the infrared region.
Bracket series involves electrons returning to n=4 in the infrared region.
Pfund series involves electrons returning to n=5 in the infrared region.
Humphrey series involves electrons returning to n=6 in the infrared region.
Formulas for calculating possible lines produced during electron transitions provided.
Limitations of Bohr model include inability to explain Zeeman effect, Stark effect, dual nature of matter, and Heisenberg uncertainty principle.

02:09:52

Electron Orbitals and Quantum Numbers Explained

Electrons can spin in two different directions, either anti-clockwise or clockwise, which is studied under the spin quantum number.
Electrons are represented and filled in orbitals, with p subshell containing p x, p y, and p z orbitals, while d subshell includes d x y, d y z, d z x, d x square y square, and d z square orbitals.
D orbitals are categorized into axial and non-axial orbitals, with d x square y square and d z square being axial, and d x y, d y z, and d x z being non-axial.
Non-axial orbitals like d x y are represented by lobes between the x and y axes, forming a double dumbbell shape.
D y z orbitals are represented by lobes between the y and z axes, while d x z orbitals have lobes between the x and z axes, all in a double dumbbell shape.
Axial orbitals like d x square y square have lobes on the x-axis, while d z square has one lobe on the z-axis and another forming a ring around it.
D orbitals contain a total of 10 electrons distributed among five orbitals, with f orbitals having seven orbitals and 14 electrons.
Quantum numbers, including principal, azimuthal, magnetic, and spin quantum numbers, determine the address, shape, and energy of electrons.
The principal quantum number (n) indicates the shell, with n = 1 for the k shell, n = 2 for the l shell, n = 3 for the m shell, and n = 4 for the n shell.
The maximum number of electrons in a shell is given by 2n^2, with the k shell containing 2 electrons, the l shell containing 8 electrons, the m shell containing 18 electrons, and the n shell containing 32 electrons.

02:31:10

Quantum Numbers and Electron Orbitals Explained

The text discusses the relationship between the quantum number "l" and the number of orbitals in a subshell: l=0 corresponds to s, l=1 to p, l=2 to d, and l=3 to f.
The formula for the number of orbitals in a subshell is 2l+1, and to find the number of electrons in a subshell, this value is multiplied by 2.
The formula to find the number of electrons in a subshell is 2(2l+1).
The value of "l" can be calculated using the formula l=0 to n-1, where "n" is the principal quantum number representing the number of shells.
When n=1, l=0, corresponding to an s orbital; when n=2, l=0 and 1, corresponding to s and p orbitals; when n=3, l=0, 1, and 2, corresponding to s, p, and d orbitals.
The representation of orbitals includes the shell number in front of the orbital type (e.g., 1s, 2s, 2p).
The azimuthal quantum number explains orbital angular momentum with the formula l(l+1)√(h/2π).
The magnetic quantum number (m) is represented by small m and explains the Zeeman effect and electron orientation in space.
The formula to calculate the value of m is -l to +l, with the total value of m being 2l+1.
The spin quantum number indicates the spin of an electron, with positive and negative values representing clockwise and counterclockwise spins, respectively. The magnetic moment is calculated using the formula √(n(n+2)) Bohr magneton, where "n" is the number of unpaired electrons.

02:49:59

Understanding Nodes in Electron Orbitals

Node is a point, plane, or region where the probability of finding an electron is zero.
Antinode is where electrons are present.
There are two types of nodes: radial nodes and angular nodes.
Radial nodes are circular, while angular nodes are linear or planar.
The formula for angular nodes is represented by "l."
The formula for radial nodes is "n - l - 1."
Total nodes are the sum of radial and angular nodes, calculated as "n - 1."
N and l are quantum numbers: n is the principal quantum number, and l is the azimuthal quantum number.
Nodal plane is where the probability of finding an electron is zero, represented as a plane.
Nodal planes for px, py, and pz are yz, xz, and xy, respectively.
For 1s orbital, there are no nodes present.
For 2s orbital, there is one radial node and no angular nodes.
The nodal plane for 2s is zero.
For 3s orbital, there are two total nodes and no angular nodes.
The nodal plane for 3s is zero.
For 2p orbital, there are no radial nodes, one angular node, and one total node.
The nodal plane for 2p is determined by the axis of the lobes.
The representation of nodes in orbitals is based on the presence or absence of nodes in different regions.
For d orbitals, the number of nodes and nodal planes can be calculated using the same formulas as for s and p orbitals.
The electronic configuration follows the principle of filling lower energy orbitals first before higher energy ones.

03:08:51

Electron Filling Rules and Orbital Stability

The first series to draw includes 1s, 2s, 3s, 4s, 5s, 6s, and 7s, followed by 2p, 3p, 4p, 5p, 6p, and 7p.
The filling of electrons involves moving in a specific direction, then inward, then towards the ball, and inward again, ensuring to touch the balls when moving inside and not touching them when moving outside.
The electron filling sequence follows the order of 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, and 7p.
The energy diagram for electron filling indicates that energy increases as you move in certain directions, with the lowest orbital being filled first.
The n plus l rule determines energy levels based on the sum of the principal quantum number and the azimuthal quantum number, with lower values indicating lower energy levels.
The Pauli's exclusion principle states that no two electrons in the same orbital can have the same set of quantum numbers, emphasizing opposite spins for electrons in the same orbital.
The maximum capacity of electrons in an orbital is 2n^2, and the maximum capacity of electrons in a type of orbital is 2(2l+1).
An orbital can hold a maximum of two electrons with opposite spins, ensuring that electrons are always paired with opposite spins.
Hunds rule of maximum multiplicity dictates that each orbital should receive at least one electron before moving on to fill additional electrons, promoting stability.
Fully filled orbitals are the most stable due to spherical symmetry, followed by half-filled orbitals with maximum spin multiplicity, and then other electronic configurations with varying electron counts.

03:26:06

Abnormal Electron Configurations in Elements

Atomic number two represents one electron in the upward direction and another in the downward direction with opposite spins, while lithium with an atomic number of three fills electrons in 1s with two electrons and 2s with one electron.
For abnormal electronic configurations, chromium with an atomic number of 24 fills electrons in 1s with two, 2s with two, 2p with six, 3s with one, 3p with six, 4s with two, and 3d with five electrons, resulting in an abnormal configuration of 1s2 2s2 2p6 3s2 3p6 4s1 3d5.
Another example of abnormal configuration is copper (Cu) with an atomic number of 29, where the correct electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s1 3d10, deviating from the expected configuration due to the need for stability.
The key takeaway is to always approach challenges with a mindset of "how can I do this" rather than "I can't," emphasizing the importance of hard work and consistency in achieving goals.

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