Question

1. choose the best answer.

what is electron configuration?
the number of energy levels surrounding an atoms nucleusthe arrangement of electrons in an atomthe location of protons in relation to electronsthe outermost electrons in an atom

1. choose the best answer.

which rule states that electrons always occupy the orbital with the lowest energy available?
hunds rulepauli exclusion principleaufbau principlebus seat rule

Explanation:

1. Electron configuration is defined as the arrangement of electrons in an atom. The number of energy levels is related but not the definition. Protons' location isn't part of electron - configuration definition. Outermost electrons are valence electrons, not the full electron configuration.
2. The Aufbau principle states that electrons occupy the orbital with the lowest energy available. Hund's rule is about maximizing spin in degenerate orbitals. Pauli exclusion principle states no two electrons can have the same set of quantum numbers. There is no "bus seat rule" in electron - filling rules.

Answer:

1. the arrangement of electrons in an atom
2. Aufbau principle