Bohr's Theory and Atomic Structure

Questions and Answers

What happens to the energy of an electron as it gets closer to the nucleus?

It becomes more positive

It becomes zero

It remains constant

It becomes more negative (correct)

The energy of an electron in a hydrogen atom is always positive.

False

What is the energy of an electron associated with the stationary state of Principal Quantum number = n = ∞ called?

Ionized hydrogen atom

The most negative energy value is given by n = ___, which corresponds to the most stable orbit.

1 Signup and view all the answers

Match the following energy transitions with the correct phenomenon:

Electron moves from higher orbit to lower orbit = b) Radiation is emitted Electron moves from lower orbit to higher orbit = a) Radiation is absorbed Signup and view all the answers

What is the energy gap between two orbits given by?

Equation (2.16) Signup and view all the answers

The energy of an electron is lowered when it is attracted by the nucleus.

True Signup and view all the answers

Why does the energy of an electron have a negative sign in equation (2.13)?

It depicts its stability relative to the reference state of zero energy and n = ∞. Signup and view all the answers

What was characterised in 1919?

Electron Signup and view all the answers

The mass of a neutron is slightly less than that of a proton.

False Signup and view all the answers

Who discovered neutrons in 1932?

Chadwick Signup and view all the answers

The oil drop experiment helped to determine the charge of a _________.

electron Signup and view all the answers

Match the following scientists with their contributions:

J.J. Thomson = Proposed the Thomson model of atom Ernest Rutherford = Proposed the Rutherford model of atom Wilhalm Röentgen = Discovered X-rays Chadwick = Discovered neutrons Signup and view all the answers

What is the purpose of Millikan's oil drop experiment?

To determine the charge of an electron Signup and view all the answers

The existence of electrically neutral particles was felt necessary as one of the constituents of an atom.

True Signup and view all the answers

The properties of fundamental particles are given in _____________.

Table 2.1 Signup and view all the answers

What is the formula for the energy of the stationary states associated with hydrogen-like species?

E n = − 2.18 ×10 −18  Z2  J Signup and view all the answers

The frequency of the photon is given by the equation ν = ∆E / h.

True Signup and view all the answers

What is the expression for the radius of the stationary states associated with hydrogen-like species?

rn = 52.9 (n^2) / Z pm Signup and view all the answers

The energy of the stationary states associated with hydrogen-like species is given by the expression E n = − 2.18 ×10 −18  _________________  J.

Z2 / n^2 Signup and view all the answers

Match the following expressions with their corresponding physical quantities:

E n = − 2.18 ×10 −18  Z2  J = Energy of stationary states rn = 52.9 (n^2) / Z pm = Radius of stationary states ν = ∆E / h = Frequency of photon λ = c / ν = Wavelength of photon Signup and view all the answers

What is the unit of energy associated with the absorption and emission of a photon?

J Signup and view all the answers

The term in the parenthesis is negative in case of absorption spectrum.

False Signup and view all the answers

What is the formula for the wavenumber of the photon?

ν = RH (1 / ni^2 - 1 / nf^2) Signup and view all the answers

The frequency of the photon is given by the equation ________________________ = ∆E / h.

ν Signup and view all the answers

Study Notes

Bohr's Theory

Bohr's theory can be applied to ions containing only one electron, such as He+, Li2+, Be3+, etc.
The energies of the stationary states associated with these ions are given by the expression: E_n = -2.18 × 10^(-18) × (Z^2 / n^2) J
The radii of these ions are given by the expression: r_n = 52.9 × (n^2 / Z) pm

Energy and Frequency

The energy change (ΔE) associated with the absorption and emission of a photon can be evaluated using the equation: ΔE = R_H × (1 / n_i^2 - 1 / n_f^2)
The frequency (ν) associated with the absorption and emission of a photon can be evaluated using the equation: ν = ΔE / h
The wavenumber (ν) can be evaluated using the equation: ν = R_H × (1 / n_i^2 - 1 / n_f^2) / hc

Absorption and Emission Spectra

In the case of absorption spectra, n_f > n_i and the term in the parenthesis is positive, indicating that energy is absorbed.
In the case of emission spectra, n_f < n_i and the term in the parenthesis is negative, indicating that energy is emitted.

Line Spectrum of Hydrogen

The line spectrum observed in the case of hydrogen can be explained quantitatively using Bohr's model.
According to Bohr's model, radiation (energy) is absorbed if the electron moves from an orbit of smaller principal quantum number to an orbit of higher principal quantum number.
The energy gap between the two orbits is given by the equation: ΔE = E_f - E_i

Atomic Models

The atomic models were proposed to explain the distributions of sub-atomic particles in an atom.
J.J. Thomson proposed a model of the atom that was later improved upon by Ernest Rutherford.

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Description

Learn about Bohr's theory, its application to ions, and the formulas for energy and radii of stationary states. Understand the energy change associated with absorption and emission of photons.

Bohr's Theory and Atomic Structure

Questions and Answers

What happens to the energy of an electron as it gets closer to the nucleus?

The energy of an electron in a hydrogen atom is always positive.

What is the energy of an electron associated with the stationary state of Principal Quantum number = n = ∞ called?

The most negative energy value is given by n = ___, which corresponds to the most stable orbit.

Match the following energy transitions with the correct phenomenon:

What is the energy gap between two orbits given by?

The energy of an electron is lowered when it is attracted by the nucleus.

Why does the energy of an electron have a negative sign in equation (2.13)?

What was characterised in 1919?

The mass of a neutron is slightly less than that of a proton.

Who discovered neutrons in 1932?

The oil drop experiment helped to determine the charge of a _________.

Match the following scientists with their contributions:

What is the purpose of Millikan's oil drop experiment?

The existence of electrically neutral particles was felt necessary as one of the constituents of an atom.

The properties of fundamental particles are given in _____________.

What is the formula for the energy of the stationary states associated with hydrogen-like species?

The frequency of the photon is given by the equation ν = ∆E / h.

What is the expression for the radius of the stationary states associated with hydrogen-like species?

The energy of the stationary states associated with hydrogen-like species is given by the expression E n = − 2.18 ×10 −18  _________________  J.

Match the following expressions with their corresponding physical quantities:

What is the unit of energy associated with the absorption and emission of a photon?

The term in the parenthesis is negative in case of absorption spectrum.

What is the formula for the wavenumber of the photon?

The frequency of the photon is given by the equation ________________________ = ∆E / h.

Study Notes

Bohr's Theory

Energy and Frequency

Absorption and Emission Spectra

Line Spectrum of Hydrogen

Atomic Models

Studying That Suits You

Description

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