Across
- 4. The scientist who introduced the modern system of representing chemical elements using letters as symbols.
Down
- 1. The total number of atoms present in a single molecule of an element.
- 2. A letter or pair of letters used to represent a single atom of a chemical element.
- 3. A positively charged particle found inside the nucleus of an atom whose count determines the atomic number.
- 5. A negatively charged particle that orbits outside the atom's nucleus.