Chemistry Chapter 2-5 Test

compound

a chemical combination of two or more different elements joined together in a fixed proportion

molecule

aggregate (group) of two or more atoms in a definite arrangement held together by chemical bonds

ion

an atom, or group of atoms, that has a net positive or negative charge

octet rule

atoms will gain, lose, or share elections in order to fill their outer energy level

transition metals

can have more than one type of charge, so we use Roman numerals to indicate what the charge is

ternary compound

compound containing more than two elements

binary compound

compound containing two elements

ionic compound

compound made of ions

molecular (covalent) compounds

compounds that form molecules

acids

compounds that from H+ in water

hydrates

compounds that have a specific number of water molecules attached to them

polyatomic ion

contains more than one atom

polyatomic molecule

contains more than two atoms (O3, H2O, NH3)

monatomic ion

contains only one atom

diatomic molecule

contains only two atoms (H2, N2, HCl, CO)

properties of ionic compounds

crystal lattice structure, conducts electricity when dissolved or melted (electrolytes), high melting and boiling points, solids at room temperature, hard and brittle, rarely burn

valence electrons

electrons located in the outermost energy levels of an atom

properties of molecular (covalent) compounds

form molecules, low melting and boiling point, solids, liquids, or gases at room temperature, don't dissolve as well in water as ionic compounds, don't conduct electricity, sometimes burn

anion

ion with a negative charge (gains electron(s))

cation

ion with a positive charge (loses electron(s))

molecular formula

shows the exact number of atoms of each element in the smallest unit of a substance

empirical formula

shows the simplest whole-number ratio of the atoms in a substance

atomic number

tells you the number of protons in an element (top number)