| A | B |
| ATOMS | SMALLEST UNIT OF MATTER WITH PROPERTIES OF SINGLE ELEMENT |
| ELEMENT | PURE SUBSTANCE OF ONE TYPE OF ATOM |
| COMPOUND | 2 OR MORE SUBSTANCES CHEMICALLY COMBINED |
| NUCLEUS | center of an atom; made up of protons and neutrons |
| ATOMIC MASS | weighted average mass of element's isotopes |
| ISOTOPE | variation of an element that has the same number of protons but different number of neutrons |
| DALTON | all matter is made up of atoms and all atoms of specific elements are identical |
| RUTHERFORD | discovered the nucleus and positive protons inside of it |
| Thomson | plum pudding model: discovered electrons with negative charge that are mixed into the positive sphere of an atom |
| BOHR | Planetary model: electrons move around the nucleus in static orbits |
| SCHRODINGER | Electron Cloud Model: neutrons inside nucleus with protons, electrons move in 3 dimensional paths around nucleus |
| MENDELEEV | father of periodic table: determined the relationship of elements to organize them into a table |
| MOSLEY | determined the atomic number NOT atomic weight determined order of elements in the periodic table |
| DEMOCRITUS | STATED ATOMS ARE SMALL, HARD, INDIVISIBLE AND INDESTRUCTIBLE PARTICLES |
| LAVOISIER | KNOW AS THE FATHER OF MODERN CHEMISTRY, GENERATED LIST OF 33 ELEMENTS, & DEVISED THE METRIC SYSTEM |
| DALTON | ATOMIC MODEL OF ATOM WAS BILLIARD BALL |
| ELECTRON | NEGATIVELY CHARGED SUBATOMIC PARTICLE |
| CATHODE RAY TUBE | a high-vacuum tube in which cathode rays produce a luminous image on a fluorescent screen, used in televisions and computer terminals. |
| RUTHERFORD | DISCOVERED PROTONS |
| CHADWICK | DISCOVERED NEUTRONS |
| ALCHEMY | MIXTURE OF SCIENCE AND MYSTICISM, DOES NOT PERFORM CONTROLLED EXPERIMENTS |
| BILLIARD BALL MODEL | DALTON'S ATOMIC MODEL OF THE ATOM BEING A UNIFORMED SOLID SPHERE |
| BECQUEREL | DISCOVERED RADIO ACITIVYT |
| ALPHA | POSITIVE RADIOACTIVITY |
| BETA | NEGATIVE RADIOACITIVITY |
| GAMMA | NEUTRAL RADIOACTIVITY |
| THOMSON | KNOW FOR EXPERIMENTING WITH CATHODE RAY TUBES |
| PLUM PUDDING MODEL | POSITIVE SPHERE (PUDDING) WITH NEGATIVE ELECTRONS (PLUMS) SPREAD THROUGHOUT |
| GOLD FOIL EXPERIMENT | showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. |
| RUTHERFORD | GOLD FOIL EXPERIMENT |
| PLANETARY MODEL | ELECTRONS MOVE IN A CIRCULAR ORBITS WITHIN ENERGY LEVELS |
| ORBITAL | REGION AROUND THE NUCLEUS WHERE ELECTRONS ARE LIKELY TO BE FOUND |
| MASS NUMBER | COMBINATION OF PROTONS AND NEUTRONS |
| NEUTRON | neutral charged particle found in nucleus of atom |
| PROTON | POSITIVE CHARGE PARTICLE FOUND IN THE NUCLEUS OF AN ATOM |
| NUCLEUS | POSITIVE CENTER OF ATOM |
| average atomic mass | the weighted average of the masses of all naturally occurring isotopes of an element |
| ELECTRON | a subatomic particle that has a negative charge |
| RUTHERFORD | Discovered the nucleus |
| THOMSON | credited with the discovery and identification of the electron; |
| ATOMIC NUMBER | the order of an element in Mendeleev's table of the elements |
| MASS NUMBER | sum of the protons and neutrons in the nucleus of an atom. |
| ELEMENT | Substances that cannot be broken down unto any other substances. |
| MOLECULES | atoms pair up resulting in the formation of __________ |
| BOHR DIAGRAM | a diagram that shows the arrangement of an element's subatomic particles and the number of electrons in each shell surrounding the nucleus of an atom |
| COMPOUND | created when atoms from two or more elements are combined |
| MOLECULE | smallest possible piece of a compound; consists of at least 2 atoms |
| MATTER | anything that has mass and takes up space (volume); everything you can touch or see; It can be a solid, liquid or gas. |
| ATOM | smallest unit of matter. It has protons, neutrons and electrons. It has a neutral charge because the number of protons in the nucleus equal the number of electrons. |
| ATOMIC NUMBER | Number of protons in the nucleus of an atom |
| ATOMIC MASS | The average mass of one atom of an element |
| ELEMENT | matter that can not be broken down into more simple types of matter |