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unit 3, lesson 1+2
Term | Definition |
---|---|
Atom | The smallest particle into which an element can be divided and still be the same element. |
Electron | Negatively charged particles |
Nucleus | A small, dense center that has a positive charge and is surrounded by moving electrons. |
Proton | Positively charged particles |
Neutron | Uncharged particles |
Electron Cloud | An area around the nucleus, that electrons move within. |
Atomic Number | The number of protons in the nucleus of an atom |
Mass Number | The total number of protons and neutrons in an atoms nucleus. |
Periodic Table | An arrangement of of elements in order of their atomic numbers such that the elements with similar properties fall in the same column or group. |
Chemical Symbol | a one,two, or three letter abbreviation of the name of an element. |
Average atomic mass | the weighted average of the masses of all naturally occurring isotopes of an element |
Metal | an element that is shiny and that conducts heat and electricity well |
Nonmetal | an element that conducts heat and electricity poorly |
Metalloid | an element that has properties of both metals and nonmetals |
Group | a vertical column of elements in a periodic table, elements in a group share chemical properties. |
Period | in chemistry, a horizontal row of elements in the periodic table. |