ch 11 vocab Flashcards
anything that has mass and takes up space
matter
a small particle that is the building block of matter
atom
matter with a composition that is always the same
substance
two or more atoms that are held together by chemical bonds and act as a unit
molecules
a substance made of only one kind of atom
element
a substance made of two or more elements that are chemically joined in a specific combination
compound
matter that can vary in composition
mixture
a mixture in which the substances are not evenly mixed
heterogeneous mixture
a mixture in which two or more substances are evenly mixed but not bonded together
homogeneous mixture
the region at the center of an atom that contains most of the mass of the atom
nucleus
a positively charged particle in the nucleus of an atom
proton
an uncharged particle in the nucleus of an atom
neutron
a negatively charged particle that occupies the space in an atom outside the nucleus
electron
a region surrounding an atom’s nucleus where one or more electrons can be found
electron cloud
the number of protons in the nucleus of an atom of an element
atomic number
is one of two or more atoms of elements having the same number of protons but a different number of neutrons
isotope
an atom that has a charge because it has gained or lost electrons
ion