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unit 3 l1 and 2
Term | Definition |
---|---|
atom | is the smallest particle into which an element can be divided and still be the same element |
nucleus | a small, dense center that has a positive charge and is surrounded by moving electrons |
protons | the positively charged particles in the nucleus |
electrons | the particles in the atoms that are negatively charged |
neutrons | uncharged particles that the nucleus contains |
electron cloud | electrons that move within an area around the nucleus |
atomic number | the number of protons in the nucleus of anatom |
mass number | the total number of protons and neutrons in an atoms nucleus |
periodic table | arrangement of the elements |
chemical symbol | is an abbreviation for the elements name |
average atomic mass | of an atom is the weighted average of the masses of all the naturally occurring isotopes of that element |
metals | are elements that are shiny and conduct heat heat and electricity |
nonmetals | are poor conductors of heat and electricity |
metalloids | are elements that have some properties of metals and some properties |
group | verticle column in the periodic table |
period | horizontal row of elements on the periodic table |