Electronic Structure of Atoms

Flashcards reviewing key concepts from the lecture on electronic structure of atoms.

What is wavelength (λ)?

The distance between corresponding points on adjacent waves.

What is frequency (ν)?

The number of cycles that pass a point in one second.

What is the relationship between the speed of light (c), wavelength (λ), and frequency (ν)?

c = λν

What is the relationship between wavelength and frequency?

Long wavelength (λ) corresponds to low frequency (ν).

How do you calculate frequency (ν) given the speed of light (c) and wavelength (λ)?

ν = c/λ

What is the equation that relates energy (E), Planck's constant (h), frequency (ν), and wavelength (λ)?

E = hν = hc/λ

Which type of electromagnetic radiation has high energy and short wavelengths?

X-rays

What is a quantum?

The smallest amount of energy that can be emitted or absorbed as electromagnetic radiation.

What is the photoelectric effect?

The emission of electrons from metal surfaces on which light shines.

What did Einstein assume about light in relation to the photoelectric effect?

Light travels in energy packets.

What is the first postulate of Bohr's model?

Electrons in an atom can only occupy certain orbits corresponding to certain energies.

What is the second postulate of Bohr's model?

An electron in a permitted orbit has a specific energy and is an 'allowed' energy state.

What is the third postulate of Bohr's model?

Energy is only absorbed or emitted in such a way as to move an electron from one 'allowed' energy state to another; the energy is defined by E = hν.

What is the equation for the energy corresponding to each allowed orbit for the electron of the H atom?

E = (-2.18 × 10-18 J)(1/n2)

What is the ground state?

The lowest energy state (n=1).

Who developed quantum mechanics?

Erwin Schrodinger

What are the three quantum numbers that describe an orbital?

Principal (n), Azimuthal (l), and Magnetic (ml)

What does the principal quantum number, n, describe?

Describes the energy level (shell) on which the orbital resides; integers ≥ 1 .

What does the azimuthal quantum number, l, describe?

Defines the shape of the orbital; integers ranging from 0 to (n-1)

What does the magnetic quantum number, ml, describe?

Describes the three-dimensional orientation of the orbital; integers ranging from -l to l

What is the number of orbitals?

n^2

What is the shape of an s orbital?

Spherical in shape.

What is the shape of a p orbital?

Have two lobes with a node between them.

What are degenerate orbitals?

Orbitals on the same energy level have the same energy.

What are the possible values for the spin quantum number, ms?

+1/2 (spin up ↑) and −1/2 (spin down ↓)

What is the Pauli Exclusion Principle?

No two electrons in the same atom can have identical sets of four quantum numbers.

What are electron configurations?

Distribution of all electrons in an atom.

What is Hund's Rule?

For degenerate orbitals, the lowest energy is attained when the number of electrons with the same spin is maximized.

What are valence electrons?

Electrons in the outer shell, these electrons are gained and lost in reactions.

What is the filling order of electrons?

Electrons fill orbitals starting at the lowest possible energy levels before filling higher levels.

What are core electrons?

Electrons in the inner shells, these are generally not involved in bonding.

What does isoelectronic mean?

Describes atoms/ions having identical electron configurations.

How are ions formed?

The gain or loss of valence electrons to achieve stable electron configuration (filled shell).