| A | B |
|---|
| atom | the smallest , purest part of an element |
| element | a substance that cannot be broken down into simpler substances |
| proton | positively charged particle of an atom |
| neutron | aomic particle with no charge |
| electron | negatively charged partilce of an atom |
| atomic mass | the number of protons and neutron found in the nuleus of an atom |
| atomic number | the number of protons in an atom; identifies the element |
| electron cloud | place around the nucleus where the electrons are found |
| isotope | an atom that has a different number of neutrons than protons in the nucleus |
| radioactive | refers to nuclear energy that is caused by changes in the nucleus of an atom |
| radioactive decay | the release of nuclear particles and energy |
| alpha particle | two protons and two neutrons that are released from the nucleus of an atom |
| beta particle | a high energy electron that is released from the nucleus rather than from the electron cloud |
| half-life | the amount of time required for half of a sample of the element to decay |
| transmutation | occurs when an atom looses protons and turns into an atom of a different element |
