Term | Definition |
atomic mass | average mass of one atom of an element |
periodic table | a chart where all elements are organized into periods and groups according to their properties |
chemical symbol | a one or two letter code that stands for an element |
period | A ROW of elements in the periodic table arranged by atomic number |
group | column of elements in periodic table, which elements have certain properties in common (chemical family) |
matter | material that all objects and substances are made of; anything with mass and space |
element | substances that are the building blocks of all matter; made up of 1 kind of atom |
compound | matter made of 2 or more elements; chemically bonded (can't be separated by physical means) |
atom | smallest particle into which an element can be divided and still have the properties of that element |
electron | negatively charged particle on the outside of the nucleus of an atom |
nucleus | center of an atom, made up of protons and neutrons |
proton | positively charged particle located in the nucleus of an atom |
neutron | small particle in nucleus of an atom with no electrical charge |
energy level | the amount of energy carried by electron in an atom; determines electron's average distance from nucleus |
isotope | atoms of the same element with different numbers of neutrons in the nucleus and thus different atomic masses |
Mass number | sum of protons and neutrons in nucleus of an atom |
Atomic number | number of protons in the nucleus of one atom of an element |
metal | elements,usually solid, with a shiny surface; conduct electricity and thermal energy well |
malleable | element that has some characteristics of both metals and nonmetals |
ductile | term used to describe a material that can be pulled out into a long wire |
conductivity | ability of an object to transfer heat or electricity to another object |
reactivity | the ease and speed with which an element combines or reacts with other elements and compunds |
corrosion | way in which acids react with some metals so as to eat away the metal |
Alkali metal | Elements in Group 1 of periodic table |
Alkaline earth metal | Elements in Group 2 of periodic table |
Transition metal | one of the elements in Groups 3-12 of periodic table |
alloy | mixture of 2 or more elements, one of which is a metal |
nonmetal | element that lacks most of the properties of a metal |
Diatomic molecule | molecule consisting of 2 atoms |
halogen | Elements found in Group 17 of periodic table |
Noble gas | Elements found in Group 18 of periodic table |
metalloid | element that has some characteristics of both metals and nonmetals |
semiconductor | substance that can conduct electricity under some conditions |