| word |
definition |
| element | a puresubstance that can not be broken chemicaly or phyisacl means |
| compound | a pure substance coposed of two or more elements that are chemically combined |
| mixture | a combination of two or more substaces not combined chemically |
| atom | the smallest particle into which an element can be divided and still retain all of the properteis of that element |
| proton | the positively charged particles of the nucleus |
| electron | the negativly charged particles found in the nucleus |
| neutron | the particles of the nucleus that have no charge |
| periodic law | a law that states that the chemical and physical properties of elements are periodic functions |
| atomic numbers | the number of protrons in the nucleus |
| atomic mass | the weighted average the masses of all naturaly occuring isotopes of an element |
| isotope | atoms that have the same nuber of protrons but difrent number of nutrons |
| valence electrons | the electrons in the outermost enrgy level of the atom |
| john dalton | atom theory |
| JJ Thomson | small particles in atom |
| ernest rutherford | positive charged nucleus, atom mostly empty space electrons travel around nucleus |
| niels bohr | electrons travel in clouds |
| democritus | 1st to come up with idea of atom |
| dmiti mendelev | father of the periodic table, arrange elements by atomic mass |
| henry moseley | reaganged periodic table ny atmoic number |
HHS Shrek
