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chem unit 2
chem midterm
Term | Definition |
---|---|
alkali metals | group 1 |
alkaline earth metals | group 2 |
halogens | group 17 |
noble gases | group 18 |
transition metals | groups 3-12 |
periods | indicates the energy level and the approx. size of an atom |
protons | in the nucleus, +1 charge |
neutrons | in the nucleus, no charge |
electrons | surrounding the nucleus, -1 charge |
isotopes | atoms of the same element that have different masses |
JJ Thomson | showed that atoms conisist of smaller particles (electrons) thru his experiment with cathode ray tubes |
Thomson's plum pudding model | neg. charged particles in a pos. charged sphere |
Ernest Rutherford | discovered that the atom has a small, dense, pos. charged nucleus |
Bohr | studied light emission of hydrogen atoms |
Schrodinger | proposed that electrons behave according to mathematical wave functions |
atomic orbitals | clouds of electron density, based on mathematical probabilities |
valence electrons | electrons in the outermost shell of the atom |
which group has a full outer shell? | noble gases |