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Atomic Vocabulary
Atomic structure vocabulary
Question | Answer |
---|---|
atom | building block of matter; can be broken down into subatomic particles |
element | made of only one kind of atom; cannot be broken down any further; found on Periodic Table |
nucleus | center of an atom; contains protons, neutrons, electrons; contains most of the mass of an atom |
proton | positively charged subatomic particle; found in nucleus; number of protons is called the atomic number; atomic number determines identity of the atom |
neutron | subatomic particle with no charge; found in the nucleus of the atom; contributes of overall atomic mass, but not to atomic charge |
electron | subatomic particle found in the electron cloud; have virtually no mass; have a negative charge; contribute to overall atomic charge, but not mass |
atomic number | number of protons found in the nucleus of the atom; tells us the name of the element; whole number above atomic symbol on Periodic Table |
atomic mass (mass number) | number of protons plus number of neutrons; almost all mass located in the nucleus of the atom; decimal number close to atomic symbol on Periodic Table; round to the nearest whole number for mass we use in class |
energy shell (level) | completely surround nucleus of atom; electrons located here; specific rules apply; 2-8-8 |
valence shell (level) | outermost energy level (shell) |
valence electrons | electrons located in the valence shell; these electrons determine an atoms level of reactivity; must be placed according to 2-8-8 rule |
subatomic | smaller than an atom |
electron cloud | all of the energy shells together; electrons found here; organized according to 2-8-8 rule |
AMU | atomic mass unit; unit used for expressing atomic mass; each proton has an amu of 1 and each electron has an amu of one |