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Expain 2 things about elements.
- all atoms in an element are the same, with the same number of protons in the nucleus
-there are 92 naturally occuring, with more created in the lab
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Most gas elements are
diatomic (2 atoms of the same element bonded)
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Explain 4 things about compounds.
-made of more than 1 kind of atom (2/more elements)
-atoms are bonded in a specific ratio
-compounds may have physical properties completely different the the elements comprising them
-there are bonding rights, so any two elements may not bond
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Explain 3 things about mixtures.
-elements, compounds, E & C combined in no ratio and not chemically bonded
-all componets retain their own physical & chmical prop.
-mixtures can be homogeneous or heterogeneous
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particles very small and evenly distributed
homogeneous
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unevenly distributed like muddy water, pizza, oil, vinegar
heterogeneous
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a change that does not change composition of a material
physical change
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a change that changes a materials composition by creating new substances
Clues:
-release of a gas (bubbling, fizzing, not boiling)
-"magical" color change
-new odors are produced
-"magical" temperature changes
chmeical change
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the study of matter
chemistry
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positively charged particles that are located inside the nucleus
protons
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neutrally charged particles that are located inside the nucleus
neutrons
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negatively charged particles located outside the nucleus in energy levels or orbitals
electrons
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Which sub-atomic particle is located outside the nucleus?
electron
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in a neutral atom...
each proton has an electron to cancel out the charge
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an atoms proton count is given by this
atomic number
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whole number of protons and neutrons in a particular isotope and is always a whole number
mass number
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weighted average of the masses of the isotopes of a particular element
average atomic mass
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samples of the same element with a differing number of neutrons
isotopes
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those created by man that have no isotopes and the avg. atomic mass = mass number
synthetic elements
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states that an outer shell can only hold 8 electrons
octet rule
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