Element 1 is hammered into a thin sheet. Element 2 is heated and turns into a liquid. Element 3 turns a greenish color as it sits in air. Element 4 is ground up into a fine, slippery powder.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which is a chemical change?
Possibilities:
- Element 1 is hammered into a thin sheet.
- Element 2 is heated and turns into a liquid.
- Element 3 turns a greenish color as it sits in air.
- Element 4 is ground up into a fine, slippery powder.

Element 3 turns a greenish color as it sits in air.