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Chemistry notes
Term | Definition |
---|---|
element | made of one kind of atom. It can't be broken down during a chemical reaction. It combines with other elements to form compounds. |
symbol | the abbreviation for the element. Always a capital letter, or a capital and a lower case. |
atomic mass | decimal number below the symbol. It is the mass of the protons and neutrons in an element |
atomic number | located above the symbol Tells the number of protons in the nucleus of an atom |
group | vertical column of elements on the periodic tables. These element have similar properties. |
period | elements in a horizontal line on the periodic table. These elements all have the same number of electron levels (valence) |
mass number | number of protons and neutrons in the nucleus of an atom. It is the atomic mass rounded to the nearest whole number |
metals | usually shiny and can be formed into shapes (malleable). They are good conductors of electricity. |
nonmetals | most have the properties opposite of metals. Nonmetals are dull and cannot be shaped. |
semimetals | have some properties of both metals and nonmetals.Some semimetals are shiny but cannot be shaped. |
noble gases | elements that do not combine easily with other elements. |