Podcast
Questions and Answers
In a discharge tube experiment, what leads to the creation of cathode rays?
In a discharge tube experiment, what leads to the creation of cathode rays?
- Collection of cations
- Introduction of noble gases
- Application of low voltage
- Collection of electrons (correct)
Which property is exclusive to anode rays compared to cathode rays?
Which property is exclusive to anode rays compared to cathode rays?
- Their effect on photographic plates
- Their ability to rotate a wheel
- Their independence of gas nature
- Their dependence on gas nature (correct)
If the voltage is increased while studying cathode rays, what happens to the e/m ratio?
If the voltage is increased while studying cathode rays, what happens to the e/m ratio?
- It decreases proportionally
- It increases proportionally
- It fluctuates irregularly
- It remains unaffected (correct)
What is the key feature of Thomson's atomic model?
What is the key feature of Thomson's atomic model?
What crucial information about the atom's structure was revealed through Rutherford's gold foil experiment?
What crucial information about the atom's structure was revealed through Rutherford's gold foil experiment?
In Rutherford's model, what maintains the stability of electrons revolving around the nucleus?
In Rutherford's model, what maintains the stability of electrons revolving around the nucleus?
How is the energy of a quantum related to its frequency, according to Planck's theory?
How is the energy of a quantum related to its frequency, according to Planck's theory?
What aspect of light is best demonstrated by the photoelectric effect?
What aspect of light is best demonstrated by the photoelectric effect?
If the energy of an incident photon on a metal surface is greater than the work function, what occurs?
If the energy of an incident photon on a metal surface is greater than the work function, what occurs?
In the context of the photoelectric effect, how does increasing the intensity of incident light affect the emitted electrons?
In the context of the photoelectric effect, how does increasing the intensity of incident light affect the emitted electrons?
What happens to the kinetic energy of emitted electrons if the wavelength of incident light decreases in the photoelectric effect?
What happens to the kinetic energy of emitted electrons if the wavelength of incident light decreases in the photoelectric effect?
A metal has a work function of 2J. If a photon of 10J is incident on the metal, how many electrons will be emitted per photon?
A metal has a work function of 2J. If a photon of 10J is incident on the metal, how many electrons will be emitted per photon?
According to Wien's displacement law, as the temperature of a black body increases, what happens to the wavelength at which it emits the most radiation?
According to Wien's displacement law, as the temperature of a black body increases, what happens to the wavelength at which it emits the most radiation?
What is a key postulate of Bohr's atomic model?
What is a key postulate of Bohr's atomic model?
According to Bohr's atomic model, what happens when an electron transitions from a higher energy orbit to a lower energy orbit?
According to Bohr's atomic model, what happens when an electron transitions from a higher energy orbit to a lower energy orbit?
How does the radius of an electron orbit in a hydrogen atom change as the principal quantum number (n) increases, according to Bohr's model?
How does the radius of an electron orbit in a hydrogen atom change as the principal quantum number (n) increases, according to Bohr's model?
What does the negative sign in the total energy of an electron in a Bohr orbit signify?
What does the negative sign in the total energy of an electron in a Bohr orbit signify?
If the ionization energy for hydrogen atom is 13.6 eV, what does this value represent?
If the ionization energy for hydrogen atom is 13.6 eV, what does this value represent?
How are the wavelengths of emitted light related in the Balmer series?
How are the wavelengths of emitted light related in the Balmer series?
What is the significance of the Rydberg constant in atomic spectra?
What is the significance of the Rydberg constant in atomic spectra?
According to de Broglie's hypothesis, what property is associated with a moving particle?
According to de Broglie's hypothesis, what property is associated with a moving particle?
If the uncertainty in the position of an electron increases, what happens to the uncertainty in its momentum, according to the Heisenberg Uncertainty Principle?
If the uncertainty in the position of an electron increases, what happens to the uncertainty in its momentum, according to the Heisenberg Uncertainty Principle?
Which quantum number primarily determines the size and energy of an orbital?
Which quantum number primarily determines the size and energy of an orbital?
What information does the azimuthal quantum number (l) provide about an electron in an atom?
What information does the azimuthal quantum number (l) provide about an electron in an atom?
What does the magnetic quantum number (m) specify?
What does the magnetic quantum number (m) specify?
What does the spin quantum number (s) describe?
What does the spin quantum number (s) describe?
According to Hund's rule, how are electrons arranged within a subshell?
According to Hund's rule, how are electrons arranged within a subshell?
What does the Pauli Exclusion Principle state regarding electrons in the same atom?
What does the Pauli Exclusion Principle state regarding electrons in the same atom?
What are degenerate orbitals?
What are degenerate orbitals?
Flashcards
Cathode Rays
Cathode Rays
Cathode rays are a collection of electrons.
Anode Rays
Anode Rays
Anode rays (canal rays) are a collection of cations.
Thomson's Atomic Model
Thomson's Atomic Model
Thomson's atomic model proposes that positive charge is distributed uniformly throughout the atom.
Rutherford's Experiment
Rutherford's Experiment
Signup and view all the flashcards
Energy of Quanta
Energy of Quanta
Signup and view all the flashcards
Photoelectric Effect
Photoelectric Effect
Signup and view all the flashcards
Photon Energy Equation
Photon Energy Equation
Signup and view all the flashcards
Work Function
Work Function
Signup and view all the flashcards
Photoelectric Emission Condition
Photoelectric Emission Condition
Signup and view all the flashcards
Bohr's Model Applies To
Bohr's Model Applies To
Signup and view all the flashcards
Orbits Around Nucleus
Orbits Around Nucleus
Signup and view all the flashcards
Electron Revolution Condition
Electron Revolution Condition
Signup and view all the flashcards
Radius of First Orbit (H)
Radius of First Orbit (H)
Signup and view all the flashcards
Ionisation Energy
Ionisation Energy
Signup and view all the flashcards
Spectral Line
Spectral Line
Signup and view all the flashcards
De-Broglie’s Wavelength
De-Broglie’s Wavelength
Signup and view all the flashcards
Pauli Exclusion Principle
Pauli Exclusion Principle
Signup and view all the flashcards
Aufbau Principle
Aufbau Principle
Signup and view all the flashcards
Hund's Rule
Hund's Rule
Signup and view all the flashcards
Study Notes
Atomic Structure
- Discovery of electron and proton occurs in a vacuum with "no air."
- High voltage is supplied to a discharge tube.
- Due to high voltage (electrical energy) gas becomes H -> H+ + e-
- Collection of e- becomes cathode rays
- Collection of cation becomes anode rays (canal rays)
Cathode Rays
- Collection of electrons
- Does not depend upon the nature of the gas.
- Me = 9.1 x 10^-31 kg
- Charge = -1.6 x 10^-19 C
- Effect shown on photographic plate.
- Rotates a wheel
- e/m ratio of cathode rays = 1.6 x 10^19 C / 9.1 x 10^-31 = 1.7 x 10^11 C/kg
- e/m ratio does not depend upon the nature of the gas.
- e/m is directly proportional to voltage of battery.
Anode Rays
-
Collection of cation, in this case H2 gas -> collection of H+
-
Depends upon the nature of the gas.
-
mP = 1.6 x 10^-27 kg
-
charge = +1.6 x 10^-19 C
-
Effect shown on photographic plate.
-
Rotates a wheel.
-
e/m Ratio of Anode Rays (H+) = 1.6 x 10^-19 / 1.6 x 10^-27 = 10^8 C/kg
-
e/m ratio depends upon nature of gas.
-
e/m is directly proportional to the voltage of battery.
-
e/m Ratio of Anode Rays is variable
-
H+ displays the highest e/m Ratio, He+ is less.
-
The increasing order for the value of e/m for e-, p, n, and alpha particle is n, alpha, p, e
-
e/m Ratio of Cathode Rays decreases, when voltage of Battery increases
-
e/m directly proportional to 1/ voltage of Battery
Thomson's Atomic Model
- positive charge distributed uniformly in whole atom
- negative electrons embedded in cloud of positive charge, like a watermelon.
- stability achieved by electrostatics force.
- Model: Watermelon Model or Plum Pudding Model
Rutherford's Gold Foil Experiment
-
Also know as alpha-scattering experiment and led to discovery of the nucleus
-
Observation: Most of alpha-particles (He+2) travel through the foil undeflected. Interpretation: Atom is mostly empty space.
-
Observation: Some alpha-particles are deflected by small angles. Interpretation: Nucleus is positively charged as is the alpha particle.
-
Observation: Occasionally, an alpha-particle travels back from the foil. Interpretation: Nucleus carries most of the atom's mass. (20000 alpha of 1 particle (180°))
-
Rutherford Atomic Model
-
Atom is spherical: contains Nucleus (p+) and Extra nuclear part (e-)
-
(Atom) = 10^-10 m
-
(R) Nucl = 10^-15 m.
-
Stability is explained by solar system. electrons revolve around nucleus.
-
Rutherford's Scattering Experiment is related to the size of the Nucleus
Dual Nature of Light
-
Quanata (photon)
-
Particle Nature
-
Plank's Quantum Theory:
-
quanta = small energy packet.
-
Energy of quanta is different.
-
each quanta have energy integral multiple of minimum Energy.
-
E = n x eE min
-
E = hv [h= 6.6 x 10^-34 J sec]
-
E = hc/λ
-
Wave Nature: electromagnetic wave
-
electric field component
-
magnetic field component
-
Direction of Propagation
-
Calculation of energy in Joule corresponding to light of wavelength 450 nm : 4.42 × 10^-18
-
value of Plank's const is 6.63×10^-34 JS
-
light is 3x10^8 m/s, finding value closest to λ in nanometer of Quantum of light with Frequency of 6x10^15 sec^-1: 50nm
-
hν = Wo + KE
Photoelectric effect
-
emission of electron in metal surface, when photon incident on it.
-
surface phenomenon.
-
particle nature of light.
-
1 Photon = emit only 1 e-: hν = Photo
-
hν = Wo + KE
-
Wo implies the work function.
-
h c / λ = h ν + KE [ νo Threshold freq.]
-
h c / λ0 = + KE [ λo Threshold wavelength]
-
E directly proportional to 1/λ
-
energy of photon incident on metal surface, if (wo = 2J)
-
Calculation KE of emitted e-: 8J
-
Work Function (Wo) of some metals:
-
E > Wo -> e- will emit
-
Relation b/w Energy of electron & orbit No (n):
-
En = -13.6 x Z^2/ n^2 ev/atom
-
E1: E2: E3 = (Z1/n1)^2 : (Z2/n2)^2 : (Z3/n3)^2
-
What is work function of Metal, if the light of wavelength 400 A° generates photoelectron of velocity 6×10^5m/s from it?0
-
Calculation of Ionisation Energy
Bohr's Atomic Model
- applicable to Singly e- Species. [ H, He+, Li+2, Be+3]
- Circular path (orbit) Present surrounding Nucleus
- Orbit : alway whole No. (n≠0, Fractional).
- electron is revolving only in those orbit which have angular momentum is equal to integral multiple of h/2Ï€.
- Select correct angular momentum of revolving electron: α) h/K
Radius of Atom (rn)
-
rn = 0.53 x n^2 / Z A°
-
Bohr's Radius implies n =1 and Z =1
-
γ, = 0.53 A°
-
γn is directly proportional to n^2
-
γn is directly proportional to n^2/Z
-
Finding Ratio of radii of 1st orbits of H, He+ & Li+2:
-
6:3:2
-
Ground state of Hydrogen is 0.53A finding Radius for Li+2 ion: 0.17A°
-
Radius of 2nd Bohrs Orbit in term of Bohrs radius: 4ao/9
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
