* Physical Change: A physical change alters the appearance or form of a substance but doesn't change its chemical composition.

* Chemical Change: A chemical change results in the formation of new substances with different chemical properties.

When you cut lithium, you are simply changing its shape and size. The chemical composition (the lithium atoms) remains the same.

Important Note: Lithium is highly reactive and can react with air and moisture. While cutting it is a physical change, the exposed surface will quickly react chemically, causing a change in the metal's properties.