Chapter 31: Atomic Physics Reference Tools & Resources

Reference Tools & Resources

I. Key Terms and Phrases

nucleus: the central region of an atom that contains most of its mass and all of its positive charge.

line spectrum: the dicrete spectrum of the wavelengths of light given off by atoms.

Bohr orbit: the circular orbits of electrons around the nucleus of an atom in Bohr's model.

atomic number: the number of protons in the nucleus of an atom.

ground state: the case when the electrons in an atom are in their lowest possible energy levels.

excited state: the case when one or more electrons in an atom are in energy levels higher than the lowest.

principle quantum number: a quantity of integer value that determines the total energy of a state of hydrogen and sets the boundaries for the values of other quantum numbers.

orbital angular momentum quantum number: a quantity of integer value that determines the possible values of a component of the orbital angular momentum of an electron in an atom.

electron spin quantum number: the quantity that determines the intrinsic angular momentum of an electron.

state of an atom: the specification of the quantum numbers for every electron in an atom.

probability cloud: the modern interpretation of matter waves for the electrons around the nucleus of an atom.

shell: electrons with the same principle quantum number are in the same shell.

subshell: specification of the orbital angular momentum quantum number.

Pauli exclusion principle: the principle that only one electron can occupy a given state in an atom.

electronic configuration: specification of n, , and the number of electrons in each subshell.

periodic table: a table of the elements that organizes them by their chemical properties.

laser: light amplification by the stimulated emission of radiation.

II. Important Equations

Name/Topic	Equation	Explanation
Bohr's model		The radii of the Bohr orbits of single-electron atoms.
Bohr's model	n = 1, 2, 3, ...	The allowed energy levels of single-electron atoms in Bohr's model.
hydrogen spectrum		The wavelengths in the spectrum of hydrogen.
orbital angular momentum		The magnitude of the orbital angular momentum from the associated quantum number.

III. Know Your Units

Quantity	Dimension	SI Unit
Rydberg constant (R)	[L-1]	m-1

IV. Miscellaneous Tips

The radius of the smallest Bohr orbit, for n = 1, is called the Bohr radius; it is typically denoted as a₀ and has a value of

a₀ = 5.29 x 10^-11 m.

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