| A | B |
|---|
| protons | have a positive charge. give the atom much of its mass |
| neutrons | have a neutral charge. contribute to the mass of an atom. |
| electrons | spin around the nucleus. have a negative charge. have no mass |
| element | composed of atoms, has a specific # of protons in the nucleus, has a symbol that is one or two letters. |
| nucleus | the center of an atom |
| compound | a pure substance consisting of 2 or more elements chemically combined. |
| formula | a way to abbreviate a compound |
| molecule | the smallest form of a compound |
| photosynthesis | the process by which a plant makes its own food (glucose) using carbon dioxide and water. sunlight is needed for this to occur. |
| respiration | when plants absorb free molecules of oxygen and use them to create water, carbon dioxide and energy which helps plants grow. can happen without sunlight |
