| A | B |
|---|
| sodium | Na |
| iodine | I |
| mercury | Hg |
| iron | Fe |
| potassium | K |
| silver | Ag |
| helium | He |
| gold | Au |
| lead | Pb |
| fluorine | F |
| chlorine | Cl |
| the presence of a positive nucleus | Rutherford's gold foil experiment |
| negatively charged particle | electron |
| positively charged particle | proton |
| neutral particle | neutron |
| when all the electrons in an atom have the lowest possible energies | ground state |
| arrangement of elements based on atomic number | periodic table |
| atoms of the same element with different numbers of neutrons | isotopes |
| number of protons in the nucleus of an atom | atomic number |
| relative mass of a proton or neutron | atomic mass unit |
| sum of the relative masses of the protons and neutrons in an atom | mass number |
| areas in which electrons are found | energy levels |
| Rutherford | shot alpha particles at gold foil |
| created the modern atomic theory based on the work of others | Dalton |
| his idea of the four element theory set chemistry back 2000 years | Aristotle |
| said electrons orbited the nucleus like planets around the sun | Bohr |
| found electrons by using a magnet and a beam of light to create an atomic model | Thomson |
| the central core of the atom | nucleus |
| weighted average of the mass numbers of all the isotopes that occur in nature for a particular element | atomic mass |
| mass of a proton or a neutron | 1 amu |
| mass of an electron | 1/2000 of a proton |
| the problem with ancient Greeks' idea of atoms | no experimental data to back up their thoughts |
| An atom has 30 protons and 20 neutrons, what is its mass number | 50 |
| how is the current periodic table arranged | increasing atomic number |
