Final answer:
Aluminum does not continue to react with concentrated nitric acid due to its protective oxide layer. Other less reactive metals can form nitrogen dioxide and nitrates when reacting with concentrated nitric acid.
Step-by-step explanation:
When aluminum comes into contact with air, it forms a protective oxide layer which prevents further reaction including that with concentrated nitric acid. Concentrated nitric acid does not further oxidize aluminum to aluminum oxide due to this protective layer.
However, nitric acid does react with many metals, typically resulting in nitrates, nitrogen oxides, and various reduction products depending on the acid concentration and the reactiveness of the metal.
Less reactive metals tend to form nitrogen dioxide when reacting with concentrated nitric acid, as seen with copper, silver, and lead. By contrast, when these less active metals react with dilute nitric acid, compounds like NO are produced.
Aluminum, protected by its oxide layer, behaves differently and does not continue to react with concentrated nitric acid, illustrating a unique behavior among metals when exposed to this reactive acid.