metalloids		an element that has both metallic and nonmetallic properties.
halogens		a negative ion
proton		several series of elements in which inner orbitals (d or f orbitals) are being filled.
compound		the number of protons in a nucleus. Z=the atomic number (the number of protons)
noble gases		a molecule composed of two atoms.
atomic number, Z		an element that does not exhibit metallic characteristics. chemically, a typical nonmetal accepts electrons froma metal.
cation		atoms of the same element (the smae number of protons) tht have different numbers of neutrons. They have identical atomic numbers but different mass numbers.
ion		a group 8 element
metals		a compound that results when a metal reacts with a nonmetal to form cations and anions.
chemical formula		a group 7 element
nonmetals		the sum of the number of neutrons and the number of protons in a given nucleus. A=the mass number (sum of protons and nuetrons)
anion		a substance which contains composition that can be broken down into elements by chemical processes.
electron		negatively charged particle that occupies thte space around the nucleus of an atom
groups		vertical columns of elements having the same valence electron configuration and similar chemical properties.
mass number, A		fundamental unit of which elements are composed
Dalton's atomic theory		set of abbreviated symbols for the chemical elements.
isotopes		element that gives up electrons relatively easily and is tyically lustrous, malleable, and a good conductor of heat and electricity
alkali metals		chart showing all the elements arranged in columns in such a way that all the elements in a given column exhibit similar chemical properties.
atom		a group 1 metals
element symbols		negatively charged particle that occupies space around the nucleus of an atom.
Periodic Table		the small, dense center of positive charge in an atom.
diatomic molecule		a group 2 metals
nuclear atom		Elements are made of tiny particles called atoms. 2. All atoms of a given element are identical. 3. The atoms of a given element are different from those of any other element. 4. Atoms of one lement can combine with atoms of other elements to form compounds. A given compund always has the same relative numbers and types of atoms. 5. Atoms are indivisible in chemical processes. that is, atoms are not created or destroyed in chemcial reactions. a chemical reaction simply changes the way the atoms are grouped together.
law of constant composition		the modern concept of the atom as having a dense center of positive charge (the nucleus) and electrons moving around the outside.
alkaline earth metals		a postive ion
neutron		representation of a molecule in which the symbols for the elements are used to indicate the types of atoms present and subscripts are used to show the relative numbers of atoms.
ionic compound		positively charged particle in an atomic nucleus.
nucleus		particle in an atomic nucleus with a mass approximately equal to that of the proton but with no charge.
transition metals		an atom or a group of atoms that has a net positive or negative charge