Aluminum Foil #4, 7, 11

Aluminum Foil

#4- A sample of matter which contains only one kind of atoms. Identify the kind of atom with its symbol and atomic mass.
-Aluminum foil is an element. It is located on the periodic table of elements. Elements are is something that contains only one type of atom. Its symbol is: Al, and its atomic mass is: 26.98 grams.
-Cite: I found this information in my notes on my periodic tables.

#7- A sample of an element which could be the "X" in the formula X2O3
-If you plug in aluminum (Al) to the formula you get Aluminum oxide. (Al2O3) And aluminum is found in aluminum foil which is in the picture above.
-Cite: I found this information in my notes

#11- A sample of matter which contains atoms with an oxidation state of +3.
-Aluminum has an oxidation state of +3. When it looses 3 electrons it becomes positive. The complete formula is Al2O3
-Cite: I found this information in my notes