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Chemistry_ch.4
| Question | Answer |
|---|---|
| Who thought matter was sformed of air, eath, fire, and water? | Greek philosophers |
| it was commonly accepted that ______ could be endlessly divided into smaller and smaller pieces | matter |
| ___________was the first person to propose matter was _________________ | Democritus; not infinitely divisible |
| Democritus believed that matter was made up of tiny particles called? | atomos |
| ________ revised and revived Democtitus's ideas. | JOhn Dalton |
| Daltons ________ included: all matter is composed of extremely small particles called ________ | Atomic theory; atoms |
| All atoms have the same size, mass, and chemical properties. | True |
| Atoms of a specific element are the same from those of any other element | False; different |
| Atoms cannot be_________ or ________ | created or destroyed |
| In a ___________________ atoms are seperated,________ or reorganized | Chemical reaction; combined |
| The smallest particle of an element that retains the properties of the element is called an | atom |
| ______ are so small that they can only be seen by using a ____________________ | atoms; scanning tunneling microscope |
| negatively charge particles that are part of all forms of matter are called? | electrons |
| the electron was discovered by _____________ | j.j thomson |
| _________ proposed the ____________ atomic model | thomson; plum pudding |
| ___________ determined the mass of an electron to be 9.1 X 10 (-28) g | Robert Millikan |
| Ernest ________ performed ________ experiment. he discovered that atoms had a small dense center region called a _________ | Rutherford; gold foil; nucleus |
| Rutherford also concluded that the nucleus of an atom conains ________ charged particles called protons | positive |
| subatomic particle that carries a charge equal to but opposite than that of an electro | proton |
| ________ showed that the nucleus also contained a neutral particle called the ________ | James chadwick; neutron |
| A neutron has a mass nearly equal to that of a ____________ but carries no ___________ charge | Proton; electrical |
| number of protons in an atom is | atomic number |
| ___________ determines an elements position on the ____________ | atomic number; periodic table |
| Atomic Number= number of protons= number of electrons | true |
| atoms with the same number of protons but different number of ____________ are called _________ | neutrons; isotopes |
| represents the sum of the number of protons and neutrons in the nucleus | mass number |
| = atomic number from the mass number | number of neutrons |
| mass of subatomic particles is measured int | atomic mass units |
| atomic mass unit is defined as | 1/2 the mass of a carbon-12 atom |
| weighted average mass of the isotopes of that element | atomic mass |
| _____________ involve an atom of one element changing into an atom of another element | nuclear reactions |
| substances that emit radiation | radiactive |
| the ____ and ________ emitted by a radioactive material is called radiation | rays and particles |
| radioactive atoms emit radiation because their _______ are unstable | Nuclei |
| made up of alpha particles | alpha radiation |
| consists of fast moving electrons called beta particles | beta radiation |
| consists of gamma rays ( high energy radiation that possess no mass) | gamma radiation |
| a ________equation show the atomic number and mass number of the particles involved | nuclear |
Created by:
Tonya#33
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