| Term |
 |
|
| Definition |
|
|
| was a Greek philosopher |
Democritus was |
| proposed the existence of atom |
Democritus did |
| thought that matter can be subdivided until a single indivisible particle was reached |
Democritus did |
| who was an English school teacher |
Dalton was |
| who proposed an atomic model in the early 1800's |
Dalton did |
| Who thought that atoms of the same atoms were identical |
Dalton did |
| thought that atoms of different elements were different |
Dalton did |
| thought compounds formed when atoms of two or more elements combine |
Dalton did |
| plum pudding model |
thomason's idea |
| negatively charge electrons embedded in positively charged material |
plum pudding model |
| discovered the electron |
thomason did |
| discovered that the atom is basically empty space |
rutherford did |
| credited with the discovery of the nucleus |
rutherford was |
| gold foil experiment |
rutherford's experiment |
| used alpha particles to study structure of the atom |
rutherford did |
| concluded that the atom was mostly empty space with a dense positively charged nucleus in the center |
rutherford did |
| was danish scientist |
bohr was |
| proposed that the negative electrons were held in orbit by the positive nucleus |
bohr did |
| thought that electrons moved in definite orbits around the nucleus |
bohr did |
| solar system model |
bohr's model |
| proposed that electrons are located in energy levels |
bohr did |
| thought electrons were located at certain distances from the nucleus |
bohr did |
| wave model |
modern atomic model |
| wave model |
proposes that electrons do not move in definite orbits |
| wave model |
impossible to determine exact electron location |
| wave model |
location of electron depends on the amount of energy the electron possesses |
| proton |
is a positively charged subatomic particle |
| protons |
are located in the nucleus |
| a proton |
is slightly smaller in mass than the neutron |
| neutron |
is the largest subatomic particle |
| an electron |
is negatively charged subatomic particle |
| an electron |
is the smallest subatomic particle |
| an electron |
are found in "energy cloud" |
| atomic number |
determines the identity of atom |
| isotopes |
atoms of same element that "weigh" differently |
| isotopes |
are atoms of the same element that differ in the number of neutrons |
| mass number |
number of particles in the nucleus of an atom |
| mass number |
is the number of protons + number of neutrons |
| an electron clouds |
is the space around the nucleus where electrons are found |
| two electrons |
is the maximum number of electrons in the first energy level |
| eight electrons |
is the maximum number of electrons in the second energy level |
| eighteen electrons |
is the maximum number of electrons in the third energy level |
| thirty two electrons |
maximum number of electrons in the fourth energy level |
| quark |
believed to makeup subatomic particles |
| electromagnetic forces |
force acting between charged bodies |
| repulsion |
is the force between two like charged bodies |
| attraction |
is the force between two unlike charged bodies |
| strong force |
is responsible for holding the nucleus together |
| weak force |
is responsible for the process known as radioactive decay |
| protons |
are positively charged subatomic particle |
| Which subatomic particle is least massive? |
electron is |
| Which subatomic particle is most massive? |
neutron is |
| Almost all the mass of an atom is located where? |
within thenucleus |
| The atomic number of sulfur is 16. How many electrons are there in an atom of sulfur-34? |
eighteen |
| Atoms emit energy as light when |
electrons move to a lower energy level |
| Which part of Dalton's theory was modified after the discovery of isotopes? |
Dalton assumed that all atoms of the same element were identical in all ways. However, they may differ in the number of neutrons present. |
| What did Thomason's experiment prove? |
proved that the atoms are made of even smaller particles. |
| What must be true if an atom is electrically neutral? |
the atom must contain within itself an equal number of electrons and protons. |
| electron configuration |
is the arrangement of electrons in the orbitals of the atom |
| energy levels |
are the possible energies that electrons in an atom can have. |
| an electron cloud |
is a visual model of the most likely locations for the electrons in an atom. |
| the gain or lose energy may result in ______________. |
an electron in an atom can from from one energy level to another |
