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Atomic Structure
atomc structure
Question | Answer |
---|---|
proposed the existence of atom | Democritus |
thought that matter can be subdivided until a single indivisible particle was reached | Democritus |
who proposed an atomic model in the early 1800's | Dalton |
Who thought that atoms of the same atoms were identical | Dalton |
thought that atoms of different elements were different | Dalton |
thought compounds formed when atoms of two or more elements combine | Dalton |
plum pudding model | thomason's idea |
negatively charge electrons embedded in positively charged material | plum pudding model |
discovered the electron | thomason |
discovered that the atom is basically empty space | rutherford |
credited with the discovery of the nucleus | rutherford |
gold foil experiment | rutherford's experiment |
used alpha particles to study structure of the atom | rutherford |
concluded that the atom was mostly empty space with a dense positively charged nucleus in the center | rutherford |
was danish scientist | bohr |
proposed that the negative electrons were held in orbit by the positive nucleus | bohr |
thought that electrons moved in definite orbits around the nucleus | bohr |
solar system model | bohr's model |
proposed that electrons are located in energy levels | bohr |
thought electrons were located at certain distances from the nucleus | bohr |
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 |
Which subatomic particle is most massive? | neutron |
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 |
In 1897, J.J. Thomson used a cathode ray tube to deduce the presence of a negatively charged particle:__________________ | electron |
Atoms are neutral, so there must be positive particles in the atom to balance the ______________ of the electrons | negative charge |
Alpha particles are __________ nuclei | helium |
________________ model was called a “nuclear model” | rutherford's |
Elements are different because they contain different numbers of _______________ | protons |
The ______________________ of an element is the number of protons in the nucleus | atomic number |
__________________ is the number of protons and neutrons in the nucleus | mass number |
Atoms of the same element can have different numbers of ________________. | neutron |
__________________ is the average of all the naturally occurring isotopes of that element. | atomic mass |