Final answer:
Noble gases are called noble gases because they have a filled outer subshell and are unreactive at room temperature and pressure. They are composed of single atoms and are particularly stable due to their complete valence shell. However, they can form compounds under certain conditions.
Step-by-step explanation:
The noble gases are called noble gases because they are composed of single atoms and have a filled outer subshell, which makes them particularly stable. This stability is due to their complete valence shell, which means they have a full octet of electrons. They are unreactive at room temperature and pressure, which is why they were originally called inert gases.
However, some chemical compounds containing noble gases were prepared in 1962, showing that they can form compounds under certain conditions.