Classify the following elements as metal or noble gas: Argon, Iron, Copper, Krypton, Neon, Silver, Thorium, Radon, Helium, Xenon, Erbium, Tin, Protactinium

Argon - Noble Gas
Iron - Metal
Copper - Metal
Krypton - Noble Gas
Neon - Noble Gas
Silver - Metal
Thorium - Metal
Radon - Noble Gas
Helium - Noble Gas
Xenon - Noble Gas
Erbium - Metal
Tin - Metal
Protactinium - Metal