Across
- 2. A metal element that is essential for human. It plays a key role in skin health, immune system, and cell growth.
- 4. Atoms that have different number of neutron.
- 7. A number that is a sum of proton and neutron.
- 9. A negative charge particle in an atom.
Down
- 1. A metal element that is essential for your bone health.
- 3. The name of the diagram that shows an atom's structure.
- 5. An element that has 8 protons.
- 6. The letter in each block of the periodic table.
- 8. The first letter of this noble gas is A.