| A | B |
|---|
| matter | anything that has mass and takes up space |
| atoms | particles that make up matter |
| elements | have only 1 kind of atom |
| protons | in nucleus - positive charge |
| neutrons | in nucleus - no charge |
| electrons | orbit the the nucleus - negative charge |
| mass number | protons + neutrons |
| atomic number | = the number of protons |
| isotopes | same element but have different numbers of neutrons |
| compounds | made from different atoms |
| positive charge | more protons than electrons |
| negative charge | more electrons than protons |
| molecule | when atoms combine by sharing electrons |
| chemical properties | how a substance changes when it reacts with other substances |
| ions | electrically charged atoms |
| mixture | different objects mixed together - each retains its properties |
| solution | dissolving one substance in another |
| physical properties | properties of a substance that you can observe |
| Density | mass divided by volume |
| physical properties | density and state of matter |
| solid | atoms or molecules are fixed |
| liquid | atoms and molecules are close but can change position |
| gas | little attractive force between atoms and molecules |
| plasma | matter composed of ions and electrons |
| plasma | most common state of matter |
| nuclear energy | energy that comes from splitting atoms |
| nuclear waste | highly radioactive |
