Across
- 2. Release of heat
- 4. A measurement of acidity
- 6. Molecule composed of two atoms
- 8. Absorption of heat
- 11. A chemical bond that shares electrons
- 12. A negatively charged ion
Down
- 1. - two or more atoms in a covalent bond
- 3. An orbit of electrons around an atoms nucleus
- 5. An electron in the outer shell of an atom
- 7. A group of atoms bonded together
- 9. Hydrogen and carbon
- 10. A positively charged ion