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chem 8th grade
Question | Answer |
---|---|
atomic number | the number of protons in the nucleus of an atom |
electron cloud | a region inside an atom where electrons are like;y to be found |
Dimitri Mendeleev | created the first periodic table |
John Dalton | believed "atoms cannot be created or destroyed" #all elements made of atoms which combine to form compounds" |
therm | unit of heat |
plastic | term used to describe a material that doesn't return to its original shape after stretching |
adhesive | able to stick |
endo | internal within |
exo | giving out |
periodic table | table of the elements arranged according to their atomic number |
family/group | vertical column of elements on the periodic table |
period | horizontal row of elements on the periodic table |
chemical property | a property of matter that describes a substance based on its ability to change into a new substance with different properties |
physical property | a property of matter that can be observed or measured without changing the identity of the matter |
metals | elements that are shiny,ductile,malleable andare good conductors of thermal energy and electrical current |
non-metals | elements that are not shiny are poor conductors of thermal energy and electrical current |
metalloids | elements that have properties of both metals and non-metals: sometimes known as semi-conductors |
insulators | materials that reduce or inhibit the transfer of thermal energy and electrical current |
conductors | materials that conduct thermal energy and electric current well |
ions | a charged particle that forms during chemical changes when one or more valence electrons transfer from one atom to another |