Identify the smaller particles of an atom
and describe their
arrangement, charge
and mass

sub-particle      charge         mass

protons                  +1                 1

neutron                   0                 1

electron                - 1            negligible

protons and neutrons are found in the nucleus

electrons in the shells orbiting the nucleus

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)