| A | B |
|---|
| Dalton | proposed theory that all matter is made up of individual particles called atoms, which cannot be divided |
| atoms/mass | all atoms of the same element have the same mass |
| compounds | contain atoms of more than one element |
| Thomson's model | "plum pudding" model - Thomson's model had negative charges were evenly scattered throughout an atom filled with positively charged mass of matter |
| Thomson's experiments | used an electric current and a sealed glass tube of gas - When the current was on, disks became charged and a glowing beam appeared in the tube. The beam bent toward a positively charged plate placed outside the tube. |
| Rutherford's hypothesis | Thought mass and charge at any location in gold foil would be too small to change the path of an alpha particle (which he named fast-moving, positively charged particles) |
| Gold Foil Experiment | Marsden aimed a narrow beam of alpha particles at gold foil. The screen around the gold was made of a material that produced a flash of light when struck by the particles. Marsden figured out paths by observing the flash. Some of the locations of the flashes didn't support Rutherford's hypothesis. Some were deflected. |
| Nucleus | a dense, positively charged mass located at the center of the atom |
| Rutherford's model | all of an atom's positive charge is located in its nucleus |
| subatomic particles | protons, electrons and neutrons - distinguished by mass, charge and location |
| proton | positively charged subatomic particle found in the nucleus of an atom |
| electron | negatively charged subatomic particle found in the space outside the nucleus |
| neutron | neutral subatomic particle found in the nucleus of an atom |
| atomic number | equals the number of protons in an atom of an element |
| mass number | sum of protons and neutrons in the nucleus of an atom |
| isotopes | isotopes of an element have the same atomic number, but different mass numbers, because they have different numbers of neutrons. |
| Bohr Model | the electrons move in a spherical orbit at fixed distance from the nucleus |
| Energy level | possible energies that electrons can have |
| Electron cloud model | visual model of the most likely location for electrons in a model |
| orbital | region of space around the nucleus where an electron is likely to be found |
| Electron configuration | arrangement of electrons in the orbial of an atom |
| ground state | when all electrons in an atom have the lowest possible energies |
