Midterm Review. Chem. Test Questions – Flashcards
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| Who was the first person to propose the idea that matter was not infinitely divisible. |
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| Democritus |
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| Democritus believed matter was made up of tiny individual particles called, _, from which the English word atom is derived. |
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| atomos |
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| Democritus believed that atoms could be created, destroyed, or further divided. true or false. |
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| false. he believed that they couldn't be. |
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| Democritus received much criticism for his ideas from other scientists, one of them being _. Why were these criticisms received? |
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| Aristotle; They would ask what holds the atoms together, and he could not answer the question. |
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| Aristotle rejected Democritus' theory entirely. true or false. |
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| true |
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| Aristotles ideas were.. |
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| he denied the existence of atoms. |
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| John Dalton came up with.. |
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| Dalton's Atomic Theory |
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| All matter is composed of extremely small particles called atoms, atoms cannot be created divided or destroyed, and that in a chemical reaction atoms are separated, combined, or rearranged are all parts of.. |
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| Dalton's Atomic Theory |
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| Was all of Dalton's theory accurate? |
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| no |
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| Wad Dalton's atomic theory a huge step toward our current atomic model of matter? |
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| yes |
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| What was Dalton wrong about? |
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| He was wrong about atoms being indivisible, (they are now divisible into several subatomic particles) and about all atoms of a given element having identical properties (atoms of an element mayy have slightly different masses) |
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| Do all atoms of a given element have identical properties? |
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| no |
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| Are atoms indivisible? |
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| no |
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| _ is the smallest particle of an element that retains the properties of the element. |
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| an atom |
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| What does the scanning tunneling microscope allow you to do? |
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| see individual atoms |
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| Why was the accidental discovery of the cathode ray so significant? |
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| it led to the development of the television |
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| Negatively charged particles that are part of all forms of matter are now known as _ |
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| electrons |
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| Who began a series of cathode ray tube experiments to determine the ratio of its charge to its mass? |
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| J.J. Thomson |
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| Thomson concluded that the mass of the charged particle was much less than that of a _ atom, the lightest known atom. |
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| hydrogen |
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| Who was the person that identified the first electron/ discovered it? |
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| J.J Thomson |
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| How did Thomson prove that Dalton was wrong? |
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| He proved that atoms were divisible into smaller subatomic particles. |
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| Who determined the charge of an electron? |
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| Robert Millikan |
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| A single electron carries a charge of _ |
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| -1 |
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| J.J Thomson proposed a model of the atom that became known as the ... |
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| plum pudding model |
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| Did the plum pudding model of the atom last long? |
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| no |
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| Who conducted the gold foil experiment? |
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| Ernest Rutherford |
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| Rutherford concluded by his experiment that the _ was incorrect because it could not explain the results of the gold foil experiment. |
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| plum pudding model |
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| Rutherford calculated that an atom is.. |
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| consisted mostly of empty space through which the electrons move |
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| Rutherford also concluded that there was a tiny, dense region, called the _, centrally located within the atom that contained all of an atom's positive charge and virtually all its masss. |
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| nucleus |
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| Rutherford concluded that the nucleus contained positively charged particles called |
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| protons |
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| A _ is a subatomic particle carrying a charge equal to but opposite that of an electron; that is, a _ has a positive charge of _ |
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| proton, proton, +1 |
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| James Chadwick showed that the nucleus also contained another subatomic particle, a neutral particle called the _ |
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| neutron |
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| Who discovered the neutron? |
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| James Chadwick |
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| A _ has a mass nearly equal to that of a proton, but it carries no electrical charge. |
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| neutron |
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| Three subatomic particles that are the fundamental building blocks from which all atoms are made from are _, _, and _. |
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| electron, proton, neutron |
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| Where is the electron located? |
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| in the space surrounding the nucleus |
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| Where are the protons and neutrons located? |
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| in the nucleus |
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| Electron are held within the atom by their attraction to the _ _ _. |
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| positively charged nucleus |
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| Who discovered that atoms of each element contain a unique positive charge in their nuclei. |
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| Henry Moseley |
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| The number of protons in an atom is referred to as the element's .... |
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| atomic number. |
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| True or false; The period table is organized left to right and top to bottom by decreasing atomic number. |
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| false; it's organized by increasing atomic number. |
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| true or false ; Atomic # = # of protons = # of electrons |
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| TRUE (p. 98 ) |
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| Atoms with the same number of protons but different numbers of neutrons are called _ |
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| isotopes |
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| true or false. Isotopes do not differ in mass. |
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| false; they do differ |
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| The number added after the element's name to help make it easy to identify each isotope of an element is the _ |
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| mass number |
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| True or false; Number of neutrons = mass number - atomic number. |
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| true. |
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| amu stands for.. |
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| atomic mass number |
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| What is the weighted averaged mass of the isotopes of an element..? |
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| atomic mass |
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| What do you need to calculate the atomic mass of an element? |
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| number of naturally occurring isotopes, their masses, and their percent abundances |
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| A nuclear reaction involves a change in an atom's _ |
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| nucleus |
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| _ is a process in which some substances spontaneously emit radiation. |
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| radioactivity. |
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| The rays and particles emitted by the radioactive material is called _ |
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| radiation |
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| Unstable nuclei lose energy by emitting radiation in a spontaneous process ( a process that does not require energy) called .. ? |
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| radioactive decay |
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| Scientists named the radiation that was deflected toward the negatively charged plate .. ? |
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| alpha radiation |
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| Alpha radiation is made up of.. ? |
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| alpha particles |
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| Each alpha particle contains _ protons and _ neutrons, and thus has a _ charge. |
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| 2, 2, +2 |
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| Since opposite electrical charges, attract, it explains why the _ particles are attracted to the negatively charged plate. |
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| alpha |
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| An alpha particle is equivalent to a helium-4 nucleus, which is represented by |
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| 4He 2 and it's also represented by the fish thing that represents jesus! |
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| The radiation that was deflected toward the positively charged plate is called |
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| beta radiation |
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| beta radiation consists of fast moving electrons called |
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| beta particles |
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| Beta particles are represented by |
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| 0B( fancy looking B) -1 |
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| What is the charge for Beta? |
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| -1 |
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| Whats the charge for Gamma? |
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| What are high-energy radiation that posses no mass and are denoted by the symbol 0/0y |
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| gamma rays |
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| Because they possess no electrical charge, _ are not deflected by electric or magnetic fields. |
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| gamma rays |
