Question

what is true of valence electrons?

• they exist in the outer orbital.
• they have difficulty moving from one orbital to another.
• they easily move from one orbital to another.
• they are always the lowest energy electrons of the atom.

Explanation:

1. Recall the definition of valence electrons: Valence electrons are the electrons in the outermost shell (orbital) of an atom.
2. Analyze each option:

• "They exist in the outer orbital": This matches the definition of valence electrons.
• "They have difficulty moving from one orbital to another": Valence electrons are involved in bonding and can be transferred or shared, so they don't have difficulty moving in the context of chemical interactions. This is incorrect.
• "They easily move from one orbital to another": While valence electrons are involved in bonding, the term "easily move from one orbital to another" is not the defining characteristic. The key is their location in the outer orbital, not the ease of moving between orbitals in general. This is not the best answer.
• "They are always the lowest energy electrons of the atom": The lowest energy electrons are in the inner orbitals (closer to the nucleus). Valence electrons are in the outer orbitals with higher energy (compared to inner electrons). This is incorrect.

Answer:

A. They exist in the outer orbital.