| A | B |
|---|
| neutral atom | equal numbers of protons and electrons |
| alpha particle | contains 2 protons and 2 neutrons |
| radioactivity | an atom changes through transmutation |
| Thomson's Model of the atom | plum pudding model |
| Rutherford"s Model of the atom | most of the mass of an atom is in the nucleus |
| cathode-ray experiment | allowed the discovery of electrons |
| isotopes | atoms of the same element with differing numbers of neutrons |
| half-life | the time it takes for half of a radioactive sample to decay |
| beta particle | high energy electron |
| carbon-14 | an isotope of carbon |
| helium,neon,krypton | examples of Noble gases |
| Families or Groups on the Periodic table | run vertically |
| Periods or Series on the Periodic Table | run horizontally |
| Group/Family 1 | alkali metals |
| Group/Family 2 | alkaline earth metals |
| synthetic | made by humans |
| solid,liquid.gas | 3 states of matter |
| solid | tightly packed particles |
| gas | particles very far apart because of high kinetic energy |
| kinetic energy | energy of motion |
