| A | B |
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| He was the first person to propose the idea that matter was not inifintely divisible and made up of tiny particles called atoms | Democritus |
| This theory explains that the conservation of mass in chemical reactions is the result of separation, combination, or rearrangement of atoms that are not created, destroyed, or divided in the process | Dalton's atomic theory |
| The smallest particle of an element that retains the properties of the element is called.... | an atom |
| An instrument that allows individual atoms to be seen | scanning tunneling microscope |
| An exciting new field allowing scientists to move individual atoms around to form new shapes, patterns, and even simple machines | nanotechnology |
| What is the promise of nanotechnology? | molecular manufacturing-the atom-by-atom building of machines the size of molecular molecules |
| What do we call the particles that make up atoms? | subatomic particles |
| What three subatomic particles are the fundamental building blocks from which all atoms are made? | the electron, the proton, and the neutron |
| How does an atom remain electrically neutral? | the number of protons in the nucleus equals the number of electrons surrounding the nucleus |
| Who discovered that atoms of each element contain a unique positive charge in their nuclei? | Henry Moseley |
| What do refer to as the number of protons in an atom? | the elements atomic number |
| What does the atomic number tell us about an element? | the number of electrons and protons because all atoms are neutral |
| What do we call atoms with the same number of protons but different number of neutrons? | isotopes |
| What determines the chemical behavior of an atom? | the number of electrons |
| How do isotopes differ from each other? | in mass; those containing more neutrons have greater mass |
| What represents the sum of the number of protons and neutrons in the nucleus? | mass number |
| How can you calculate the number of neutrons in an isotope? | take the mass number and subtract the atomic number |
| What do we call the particles that make up atoms? | subatomic particles |
| What invention did the accidental discovery of the cathode ray lead to? | television |
| What are negatively charged particles that are part of all forms of matter? | electrons |
| What did JJ Thomson discover? | the first subatomic particle-the electron |
| Who determined the charge of an electron? | Robert Millikan and he also calculated the mass of a single electron |
| Who developed a new atomic model considering the properties of the alpha particles and the electrons and the frequency of their deflections? | Rutherford |
| What do we call a tiny, dense region centrally located within the atom that contains all of the atom's positive charge and virtually all of its mass? | the nucleus |
| What moves through the available space surrounding the nucleus and are held within the atom by their attraction to the positively charged nucleus? | electrons |
| What explained the neutral nature of matter: the positive charge of the nucleus balances the negative charge of the electrons? | the nuclear model |
| What is a subatomic particle in the nucleus that carries a charge equal to but opposite that of an electron? | proton |
| What is a subatomic particle in the nucleus which has a mass nearly equal to that of a proton but carries no electrical charge? | neutron |
| This is defined as 1/2 the mass of a carbon-12 atom? | atomic mass unit (amu) |
| What is the weighted average mass of the isotopes of an element? | atomic mass |
| What don't atoms of an element change into atoms of another element during a chemical reaction? | The number of protons in the nucleus determines the identity of an atom and chemical reactions only involve electrons |
| What are reactions that involve a change in an atom's nucleus and involve an atom of one element changing into an atom of another element? | nuclear reactions |
| What is the process where some substances spontaneously emit radiation? | radioactivity |
| What are the rays and particels emitted by the radioactive material called? | radiation |
| What is a spontaneous process that does not require energy where unstable nuclei lose energy by emitting radiation? | radioactive decay |
| What is the name of radiation that was deflected toward the negatively charged plate? | alpha radiation |
| What do we call particles that make up alpha radiation and contain two protons and two neutrons and thus has a 2+ charge? | alpha particles |
| What type of equations that show the atomic number and mass number of the particles involved and conserves both mass number and atomic number? | nuclear equation |
| What do we call radiation deflected toward the positively charged plate that consists of fast moving electrons called beta particles? | beta radiation |
| What do we call an electron with a 1- charge? | beta particle |
| What do we call high energy radiation that possess no mass and are not deflected by electric or magnetic fields because they possess no electrical charge? | gamma ray |
| What is the primary factor in determining an atom's stability? | ratio of protons to neutrons |
| Why are there so few radioactive atoms found in nature? | mos radioactive atoms have undergone enough radioactive decay to form a nucleus with a stable composition of neutrons and protons |
