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Unit 3
Atoms and Elements Notes
Term | Definition |
---|---|
Atoms | the basic building blocks of matter, because they are the smallest particles that can have the same properties as the stuff they make up. |
Protons | the subatomic particles that have a positive electric charge, and they are found in the nucleus (or center) of an atom. |
Neutrons | another subatomic particle that is also found in the nucleus (or center) of an atom, and they have no electric charge. |
Electrons | the third subatomic particle that have a negative charge and are found outside the nucleus in a region called the electron cloud. |
element | a pure substance that is made up of only one type of atom. |
chemical symbol | a one-or-two letter abbreviation that represents an element. The first letter is always capitalized, and all other letters are lowercase. |
physical property | a characteristic of a substance that can be observed and measured without changing the identity of the substance. |
Metals: | Most of the elements are classified as metals, which are found to the left of the zig-zag line on the Periodic Table. Physical Properties: solid, shiny, malleable, great conductors of heat and electricity. |
Nonmetals: | Nonmetals appear to the right of the zig-zag line on the Periodic Table. (Except for hydrogen.) Physical Properties: gas, dull, brittle, poor conductors of heat and electricity. |
Metalloids: | Metalloids appear between metals and nonmetals along the zig-zag line on the Periodic Table. They have some properties of metals and some properties of nonmetals. Physical Properties: solid, less shiny than metals, less malleable |