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48 Cards in this Set
- Front
- Back
- 3rd side (hint)
Define matter. |
Any material that takes up space in the atmosphere |
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What are the three states of matter? |
Solid, liquid, and gas |
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Define elements. Examples. |
A fundamental type of matter. a pure substance that cannot be broken down by chemical means into other substances example. carbon and hydrogen |
Periodic table. |
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How many elements are naturally occurring? |
92 |
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What are the four elements that make up 96% of most organisms? |
Carbon, hydrogen, nitrogen, and oxygen |
C, H, N, O |
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What is an atom? |
Particles of elements. - the smallest unit of an element that retains the characteristics of the element. - made up of three subatomic particles. |
3 things |
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What are the subatomic particles? What is their charge? |
1. Electron (-) 2. Proton (+) 3. Neutron ( ) |
3 |
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What is the atomic number? |
The number of protons in the nucleus. |
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How are the atomic weight and atomic number written with the atomic symbol? |
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What one thing makes elements different from one another? |
The number of protons |
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What is an isotope? |
They have different number of neutrons. Different forms of the same element |
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What is a radioactive isotope? |
Unstable; Amit energy as rays/particles when they break down into stable forms |
Decay |
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What can humans use radioactive isotopes for? |
They have been used in medicine and science, ranging from detecting broken bones to determining the age of fossils. x-rays. |
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Define molecule and define compound. |
Molecule: two or more chemically joined atoms Compound : the molecule combined of two or more different elements |
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What is an orbital? |
Most likely location for an electron relative to its nucleus. max is two electrons. |
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What is an energy shell? |
A group of orbitals that share the same level. one shell at a time. |
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What is the number of orbitals in each energy shell determine the number of electrons shell can hold |
Lowest shell - 1 orbital (2 electrons) Next two shells - 4 orbitals (8 electrons each) |
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What is the magic number for atoms to be stable? |
8 |
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What is the valence shell? |
The outmost occupied energy shell; atoms are more stable when full |
He and Ne |
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What are valence electrons? |
The electrons in the outermost shell; They form the bonds with other atoms |
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What is an ionic bond? |
Results from the electrical attraction between two ions with opposite charges it occurs between an atom whose outermost shell it's almost empty and one who's valence shell is Nearly full. |
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What is an ion? |
A particle with one or more units of electrical charge. An atom that has gained or lost electrons so it has a negative or positive charge.
it's in the right hand corner of a symbol |
Gains is - Loses is + |
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Define cation. |
1-2 electrons An element that is positive because it loses electrons |
More protons than electrons |
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Define anion. |
7-8 electrons Element is negative because it gains electrons |
More electrons than protons |
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What are covalent bonds? |
Sharing of electrons between atoms that fills both their valence shells equally
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Sharing is caring |
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What is a polar covalent bond? |
unequal sharing of electrons in a covalent bond, this gives a partial positive charge in a partial negative charge |
H2O CO2 |
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What is a nonpolar covalent bond? |
The Union in which both atoms exert approximately equal pull on their shared electrons |
H2 O2 N2 Carbon-hydrogen bond |
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What is a hydrogen bond? |
Weak bond 1. Partial positive charge when combined with O or N 2.Attracted to other partially negative charges of other molecules 3.Water molecules interact with one another extensively because of this 4. these bonds are really formed and broken 5. very strong when present in large numbers |
5 things |
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What are the unique properties of water? |
1. Water is cohesive and adhesive 2. Many substances dissolve in water 3. Water regulates temperature 4. Water expands as it freezes |
4 things |
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1. How is water cohesive and adhesive? |
Cohesive: tendency to stick together (can support small animals) surface tension Adhesive: tendency to form hydrogen bonds with other substances (wet paper towel) |
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Define solution. |
something that contains dissolved substances |
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2. How do organisms dissolve in water? two ways. |
Hydrophilic and hydrophobic |
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Define hydrophilic. |
Substances that interact readily with water (Polar covalent bond) |
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Define hydrophobic. |
Substances that are not dissolved by water. (Nonpolar covalent bond). |
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3. How does water regulate temperature? |
Due to H bonds, keeps them with in the limits that permit life. |
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4. How does water expand as it freezes? |
Because of H bonds - density is greatest at 4 degrees Celsius. |
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Water ionizes into what two ions? |
H+ and OH- |
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What is an acid? example. |
A chemical that adds H+ to a solution, making the concentration of H+ ions exceed that of OH- ions Example: lemon juice and vinegar |
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What is a base? Example. |
Makes the concentration of OH - ions exceed that of the H+ ions; add directly to solutions. example: baking soda |
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What is the pH scale? |
- Used to measure how acidic or basic a solution is. - from 0 to 14 with 7 as neutral. - based on H + concentrations - each lower pH unit has ten times the amount of H+ as the next higher units |
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What number on the pH scale is neutral? |
7 |
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What numbers on the pH scale are acidic? |
A pH lower than 7 (0-6) |
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Which numbers on the pH scale are basic? |
A pH scale greater than 7. (8-14) |
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What is a buffer? |
Pair of weak acids and bases that resist pH changes - regulate pH in organisms |
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What are noble gases? |
The elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and element 118 (temporarily named ununoctium [Uuo]). |
He, Ne, Ar, Kr, Xe, Rn, Uuo (7) |
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What is alkaline? |
Having a pH balance greater than 7 |
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Define electrically neutral. |
Protons equal electrons |
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Define chemically stable. |
2 electrons in the K shell, or 8 electrons in the L or M shell |
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