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What defines a chemical element?
An element is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particular element's atoms have the same atomic number.
How are chemical elements related to the Periodic Table?
The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number.
How is the periodic table organized?
The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number

Question: How does a chemical compound differ from an element?
Self-contained rewrite: How does a chemical compound differ from an element?