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Definition
| Anything that occupies space and has mass |
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Definition
pure substance that cannot be broken down into other substances by chemical or physical means
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Definition
| element critical to health that makes up less than 0.01 percent of body mass |
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Definition
| substance containing two or more elements chemically combined in a fixed ratio |
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List the most common elements in living things.
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Definition
Gold, helium, mercury, and oxygen
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Term
Compare and contrast elements and compounds.
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Definition
- An element is a pure substance that cannot be broken down into other substances by chemical means
- A compound is a substance containing two or more elements that are chemically combined in a fixed ratio.
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Term
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Definition
| smallest particle of an element |
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Definition
| subatomic particle with a single unit of positive electric charge (+) |
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Definition
| subatomic particle that has no charge (is electrically neutral) |
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Definition
| in an atom, the central core that contains protons and neutrons; in a cell, the part that houses the cell's genetic material in the form of DNA |
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Definition
| number of protons in an atom's nucleus; is unique for each element |
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Definition
| one of several forms of an element, each containing the same number of protons in their atoms but a different number of neutrons |
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Definition
| isotope in which the nucleus decays (breaks down) over time, giving off radiation in the form of matter and energy |
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| Describe the structure of an atom. |
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Definition
The protons and neutrons are inside the nucleus and the electrons are outside. They formed a "cloud" of electrons.
[image] |
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Term
Explain how isotopes can be used to study biological processes.
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Definition
| Radioactive isotopes are useful as "biological spies" for observing what happens to different atoms within organisms. |
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Term
| Explain the role of an element's electrons in determining its chemical reactivity. |
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Definition
Electrons differ in the amount of energy they have and how tightly they are held by the protons in the nucleus. Based on these properties, chemists describe an atom's electrons as belonging to certain energy levels. Usually it is the electrons in the highest energy level of an atom that determine how that atom reacts. |
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Term
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Definition
| chemical bond that occurs when an atom transfers an electron to another atom |
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Definition
| atom that has become electrically charged as a result of gaining or losing an electron |
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Definition
| chemical bond that forms when two atoms share electrons |
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Definition
| two or more atoms held together by covalent bonds |
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Term
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Definition
| breaking of old and formation of new chemical bonds that result in new substances |
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Definition
| starting material for a chemical reaction |
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Term
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Definition
| material created as a result of a chemical reaction |
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Term
Compare and contrast ionic bonds and covalent bonds.
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Definition
- Ionic bonds occurs when an atom transfers an electron to another atom.
- Covalent bonds forms when two atoms share electrons.
[image] |
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Term
| Summarize what happens in a chemical reaction. |
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Definition
- Certain molecules constantly become rearranged into other molecules as existing chemical bonds break
- One or more new substances are formed
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