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37 Cards in this Set
- Front
- Back
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Matter |
anything that has mass and occupies space |
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Atom |
Smallest possible piece of an element |
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Atomic Number |
# of protons in the nucleus of an atom |
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Mass Number |
Sum of the # of protons and # of neutrons in an atom
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Is an atom as a whole electrically +, -, or neutral? |
Neutral, no net electrical charge... # of protons = # of electrons |
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How do you find neutrons? |
Mass # - Atomic # |
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Isotopes are atoms of an element that have different #'s of neutrons and have different mass |
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All atoms of an element are identical but not in mass number |
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Law of Conservation of Matter |
When a chemical reaction takes place, matter is neither created or destroyed. From John Dalton |
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Law of Constant Composition |
Multiple samples of any pure chemical compound always contains the same percent by mass of each element making up the compound
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Dalton's Atomic Theory |
1. All matter is made up of atoms (small, indestructible particles) 2. Atoms can neither be created nor destroyed. 3. Atoms of a particular element are alike in size, mass, and properties. 4. Atoms of different elements are different from one another. 5. A chemical reaction involves either the union or the separation of individual atoms. |
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After 200 years we know Dalton's theory isn't entirely true |
Atoms are not the most fundamental of particles, they are composed of even smaller particles we call electrons, protons, and neutrons. |
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In 1987, what did Thompson discover? |
The first subatomic particle, known as the electron |
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In 1907, Thompson and Goldstein found what? |
Another subatomic particle that was present in all atoms, the proton. |
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1930 Chadwick demonstrated the existence of what? |
The neutron |
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The Plum Pudding Model was proposed by who? |
Thomson, he discovered: 1. Atoms contained small , negatively charged particles called electrons 2. The atoms of an element behave as if they have no electrical charge at all- they are electrically neutral. |
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Who had the gold foil Alpha Particle experiment? |
Rutherford. He knew Alpha particles are 7000 times more massive then electrons, had a positive charge, and were ejected at very high speeds. |
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Alpha Particles |
Consists of 2 protons and 2 neutrons giving it a +2 charge. |
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Isotopes |
Different versions of the same element that contain different number of of neutrons in their nuclei (different mass numbers) |
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Dmitri Mendeleev |
He arranged elements in order of increasing atomic mass |
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Law of Mendeleev |
Properties of the elements recur in regular cycles (periodically) when the elements are arranges in order of increasing atomic mass
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Group |
Vertical Column on the periodic table |
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Period |
Horizontal row on the periodic table |
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Group 1 (IA) |
Alkali Metals |
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Group 2 (IIA) |
Alkaline Earth Metals |
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Group 17 (VIIA) |
Halogens |
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Group 18 (VIIIA) |
Noble Gases |
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Metals |
Shiny solids that are bendable and malleable and conduct heat and electricity |
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Non Metals |
Tend to be brittle and do not conduct heat or electricity well |
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Metalloids |
Can act depending on circumstances like either a metal or a nonmetal. They neither conduct electricity as well as metals nor insulate electrically as well as metals nor insulate electrically as well as nonmetals. |
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Frequency |
Number of cycles a wave undergoes per second |
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Wavelength |
The distance between two crests of a wave |
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Light |
Small particles of energy called photons |
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Energy is inversely related to wavelength |
True |
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If you know the wavelength of light you know its energy |
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Atomic Spectra |
The single observed color of a light from the atom can be passed through a prism and broken down into different colors. |
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