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| Anything that takes up space and has mass. |
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| Substance that cannot be broken down into substances with different properties; composed of only one type of atom. |
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| Protons, neutrons, electrons |
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What is a proton?
Charge, location, and weight |
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Definition
| Positive subatomic particle, located in the nucleus and having a weight of approximately one atomic mass unit. |
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What is a neutron?
Charge, location, and weight |
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Definition
| Neutral subatomic particle, located in the nucleus, and having a weight of approximately one atomic mass unit. |
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What is an electron?
Charge, location, and weight |
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Definition
| Negative subatomic particle, moving about in an energy level around the nucleus of the atom. It has almost no atomic weight. |
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Definition
Number of protons within the nucleus of an atom.
The number of protons defines the element. If there is a different number of protons, it isn't the same element. |
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| Explain the charge of an atom |
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Definition
| The number of electrons determines the charge of an atom. When an atom is neutral it must have the same number of protons as electrons. |
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| How many electrons can each energy level hold in an atom? |
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Definition
| The inner shell of an atom has the lowest energy level so it can only hold 2 electrons. The other shells can hold up to 8. |
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| Mass of an atom equal to the number of protons plus the number of neutrons within the nucleus. |
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| One of two or more atoms with the same atomic number but different number of neutrons. |
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| Unstable form of an atom that spontaneously emits radiation in the form of radioactive particles or radiant energy. |
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| Substance having an attached radioisotope that allows a researcher to track its whereabouts in a biological system. |
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| Helpful uses of radiation |
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Definition
| Low levels of radiation can help when scanning the body for molecular changes. Different tracers are used for different parts of the body. A PET scan is a use for radiation to look for tumors and certain diseases. It can help sterilize instruments and it can also destroy cancer cells with little risk to the rest of the body. |
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| Radioactive substances can be very harmful to the body. They can damage DNA and cause cancer. |
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Definition
| Elements with a charge. They are also called electrolytes. |
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Definition
| Union of two or more atoms of the same element; also, the smallest part of a compound that retains the properties of the compound. |
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| Substance having two or more different elements united chemically in a fixed ratio. |
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| Chemical bond in which ions are attracted to one another by opposite charges. It is always a nonmetal to a metal. There is a transfer of ions. |
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| Chemical bond in which atoms share one pair of electrons. Double and triple bonds can occur. Atoms share two or three pairs of electrons between them. |
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| What are valance electrons? |
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Definition
| Electrons on the outside shell. They are the only ones that are reactive. The number of valance electrons determines how many bonds the atom can make. |
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Definition
| Combination of atoms in which the electrical charge is not distributed symmetrically. Water is a polar molecule. |
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| Weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another, or between parts of the same molecule. Hydrogen bonds are intramolecular bonds. It is represented by a dotted line because it is a relatively weak bond and can be broken easily. |
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Term
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Definition
1. Liquid at room temperature. Therefore we can use it.
2. The temperature of water rises and falls slowly, preventing sudden drastic changes.
3. It has a high heat of vaporization so the body doesn't overheat.
4. Frozen water is less dense than liquid ice, so ice floats on water, insulating fish during winter so they don't die.
5. Excellent transport medium,
6. Water is a solvent for polar molecules. |
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Definition
| Amount of heat energy required to raise the temperature of 1 g of water 1 degree Celcius. |
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Definition
| Type of molecule that interacts with water by dissolving in water and/or forming hydrogen bonds with water molecules. |
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Definition
| Type of molecule that does not interact with water because it is nonpolar. |
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Definition
Measurement scale for hydrogen ion concentration.
0-7: acidic. HCL is a strong acid.
7+-14: basic. NaOH is a strong base.
Strong acids and bases are destructive to cells.
The higher the concentration of H+, the lower the pH. The higher the concentration of OH-, the higher the pH. |
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Term
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Definition
| Substance or group of substances that tend to resist pH changes of a solution, thus stabilizing its relative acidity and basicity. |
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