1. no longer in use; out-of-date
residue
2. manner in which the atoms of a particular molecule are attached
isotope
3. an electrically charged particle
structure
4. form of a chemical element having the same properties and atomic number but a different atomic weight
ion
5. what remains after a part is taken; the remainder
electroplate
6. coal that burns with very little smoke or flame; hard coal
molecular structure
7. the decomposition of a compound by passage of electrical current through a solution of the compound
subscript
8. an expression showing by symbols and figures the composition of a compound
anthracite
9. written underneath or low on the line
chemical formula
10. coal that burns with much smoke and yellow flame; soft coal
obsolete
11. to cover with a coating of metal using electrolysis
electrolysis
12. in chemistry, how atoms making up a particular molecule are attached
bituminous
Number 1 goes with obsolete Number 2 goes with molecular structure Number 3 goes with ion Number 4 goes with isotope Number 5 goes with residue Number 6 goes with anthracite Number 7 goes with electrolysis Number 8 goes with chemical formula Number 9 goes with subscript Number 10 goes with bituminous Number 11 goes with electroplate Number 12 goes with structure