Science
Across
- 1. substances that are made up of only one kind of particle and have a fixed or constant structure.
- 4. table organizes all discovered chemical elements in rows
- 5. the basic unit of a chemical element.
- 6. columns of the periodic table
Down
- 2. the number of protons in the nucleus of an atom, which determines the chemical properties
- 3. a part or aspect of something abstract, especially one that is essential or characteristic.
- 7. a horizontal row of the periodic table.