Concept:Noble gases are stable, unreactive elements that exist as single, unbonded atoms.
Explanation:Noble gases are the elements in Group 18, such as helium, neon, and argon.
They have a completely filled outermost electron shell, which makes them chemically stable.
Because they already have a full shell, they do not need to lose, gain, or share electrons.
Therefore, they do not form bonds with other atoms and exist naturally as single atoms.
A single atom is called a monoatomic molecule.
Noble gases are neutral, not charged, and they are very unreactive, not reactive.
They also do not form diatomic molecules like
O2 or
N2 because they are already stable alone.
Answer:B. monoatomic molecules.