Chemistry

2. Speeds up a chemical reaction.
4. A group 7 metal that is most reactive.
6. Group 7 elements include chlorine, bromine, and iodine.
7. The speed at which the amount of reactants decreases or the amount of products increases.
8. How electrons are arranged in shells in an atom.
9. A symbol used in chemical equations to show if a substance is a solid, a liquid or a gas.
11. Group 0 elements include helium, neon, argon, krypton, xenon and radon.

1. A chemical reaction in which a more reactive element replaces a less reactive one in its compound.
2. When particles collide into each other.
3. Its the minimum amount of energy needed for a successful collision to occur.
5. In chemistry it can be used to refer to atoms, molecules, ions or subatomic particles, including protons, neutrons and electrons.
10. Biological catalysts, usually consist of proteins.