7.2: Atomic Subshell Energies and Electron Assignments
- Page ID
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The Aufbau Process
Exercise \(\PageIndex{1}\)
The procedure by which electrons are assigned to (or built up into) orbitals is known as the ____ principle.
a. Aufbau b. Bohr c. Planck d. Hund e. Pauli
- Answer
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a. Aufbau
Exercise \(\PageIndex{2}\)
Which of the following statements is true concerning the electron configuration [Xe]6p2?
- This configuration cannot be the ground-state electron configuration for a Ba atom because it violates the Pauli exclusion principle.
- This configuration cannot be the ground-state electron configuration for a Ba atom because it violates Hund's rule.
- This configuration is the ground-state electron configuration for a Ba atom.
- This configuration cannot be the ground-state electron configuration for a Ba atom because it violates the Heisenberg uncertainty principle.
- This configuration cannot be the ground-state electron configuration for a Ba atom because it violates the Aufbau principle.
- Answer
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e. This configuration cannot be the ground-state electron configuration for a Ba atom because it violates the Aufbau principle.
Exercise \(\PageIndex{3}\)
According to the Aufbau principle, which of the following subshells is typically filled next after the 4s subshell?
a. 3d b. 4s c. 3p d. 2p e. 2s
- Answer
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a. 3d
Exercise \(\PageIndex{4}\)
Which of the following statements is/are CORRECT for an oxygen atom?
- The effective nuclear charge felt by a 2s electron is greater than that felt by a 1s electron.
- The effective nuclear charges felt by 2s and 2p electrons are identical.
- The effective nuclear charge felt by a 2p electron is less than that felt by a 2s electron.
a. 1 only b. 2 only c. 3 only d. 1 and 3 e. 1, 2, and 3
- Answer
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c. 3 only
Exercise \(\PageIndex{5}\)
The small, but important, energy differences between 3s, 3p, and 3d electrons is a consequence of
- the number of electrons they can hold
- their principal quantum number
- the Heisenberg uncertainty principle
- thier effective nuclear charge
- Hund's rule
- Answer
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d. thier effective nuclear charge
Exercise \(\PageIndex{6}\)
Which of the following statements is true?
- Outer electrons efficiently shield one another from nuclear charge.
- Core electrons effectively shield outer electrons from nuclear charge.
- Valence electrons are the most difficult of all electrons to remove.
- Core electrons have the lowest ionization energies of all electrons.
- Valence electrons in the outermost shell of all elements have the highest ionization energy.
- Answer
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b. Core electrons effectively shield outer electrons from nuclear charge.