4193288
Descripción
Fichas por Jade Dickey, actualizado hace más de 1 año
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Creado por Jade Dickey
hace casi 9 años
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| Pregunta | Respuesta |
| Atoms... | Are the smallest particles into which an element can be divided and will remain the same substance ...Make up elements (which combine to form compounds) ...often called the building blocks of matter |
| Atoms... Pt. 2 | ...Were not seen prior to 1981 when the scanning tunneling microscope was invented ...comes from the Greek word atomos, meaning indivisible However... The atomic theory has been around for more than 2000 years! |
| Theory | A theory is an explanation for a broad range of hypotheses and observations that have been supported by testing |
| Democritus proposed (around 440 BC)... | ...that if a person continued to cut a coin in half over and over again, they would eventually end up with an uncuttable piece ... the name for the atom  |
| Aristotle disagrees. He thought (around mid 300 BC, after Democritus)... | particles could be divided indefinitely |
| about 2000 years have passed. What are combined elements with a constant mass ration called? | ...in the 1700’s, scientists have learned that elements combine in specific proportions based on mass What are combined elements with a constant mass ration called? Compounds! |
| Dalton’s Theory Stated... | All substances are made of atoms. Atoms are small particles that cannot be created, divided, or destroyed Atoms of the same element are exactly alike, and atoms of different elements are different Atoms join with other atoms to make new substances |
| So, is the atom really the smallest particle ? | We thought so until 1897 (yes, just 110 years ago!) Another British scientist, J.J.Thomson, discovered that there were small particles inside the atom, therefore, the atom could be divided into smaller parts! |
| Thompson experimented with the cathode ray tube and discovered... | the discovery of the electron! He is known for the “plum pudding” or “chocolate chip cookie” model of the atom. |
| A Few Years Later... |  A student of Thompson’s named Ernest Rutherford decided to check out Thompson’s theory himself so he set up an atomic shooting gallery Rutherford came up with his own model of the atom (after his performance of the gold foil experiment) He is credited with the discovery of the proton and nucleus Rutherford's model came to be known as the “solar system” model |
| Niels Bohr | Niels Bohr (who worked with Rutherford) suggested that electrons travel around the nucleus in definite paths Bohr also proposed that the electrons could jump between paths  |
| Electron Clouds and Current Theory | The exact movement of an electron cannot be predicted but, according to current theory, there are regions of the atom where the electrons are more likely to be found. These are called electron clouds. |
| Chadwick...1932 | Credited with the discovery of the neutron which is located in the nucleus with the protons |
| History of the periodic table... | Mendeleev–created the first periodic table, ordered by increasing atomic mass Mosley–rearranged the periodic table in order of increasing atomic #, this is the way the current table is arranged |
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