Chapter 11 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
a substance that consists of only one type of atom.
element
two or more atoms that are held together by covalent bonds and act as a unit.
molecule
a substance containing atoms of two or more different elements chemically bonded together.
compound
matter that can vary in composition
mixture
a mixture in which 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 in the center of an atom where most of an atom’s mass and positive charge is concentrated.
nucleus
a positively charged particle in the nucleus of an atom.
proton
a neutral particle in the nucleus of an atom.
neutron
a negitively charged particle that occupies the space in an atom outside the nucleus.
electron
the region surrounding an atom’s nucleus where one or more electrons are most likely to be found.
electron cloud
the number of protonsin an atom of an element.
atomic number
atoms of the same element that have different numbers of neutrons.
isotope
an atom that is no longer neutral because it has gained or lost electrons.
ion
