Elements are any substance that cannot be decomposed into simpler substances by ordinary chemical processes.
"Copper crystals (Mesoproterozoic, 1.05-1.06 Ga; Central Mine, Keweenaw County, Upper Peninsula of Michigan, USA) 2" by James St. John is marked with CC BY 2.0.
The Periodic Table is a table of elements arranged in order of atomic number, usually in rows.
"The Periodic Table of the Elements" by Destinys Agent is marked with CC BY-NC 2.0.
For this project I am going to tell you about the three elements that I think are the most important. They are Oxygen, Iron, Copper.