Chapter 5 Vocab

Periodic Law

periodic law

periodic law

physical and chemical properties of the elements are periodic functions of their atomic numbers

periodic table

an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column

lanthanide

a member of the rare-earth series of elements, whose atomic numbers range from 58 (cerium) to 71 (lutetium)

actinide

any of the series of heavy radioactive elements that extends from thorium (atomic number 90) through lawrencium (atomic number 103) on the periodic table

alkali metals

one of the elements of Group 1 of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium)

alkaline-earth metals

one of the elements of Group 2 of the periodic table (beryllium, magnesium, calcium, strontium, barium, and radium)

transition elements

one of the metals that can use the inner shell before using the outer shell to bond

main-group elements

an element in the s-block or p-block of the periodic table

halogens

one of the elements of Group 17 of the periodic table (fluorine, chlorine, bromine, iodine, and astatine); halogens combine with most metals to form salts

atomic radius

one-half of the distance between the center of identical atoms that are not bonded together

ion

an atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge

ionization

the process of adding or removing electrons from an atom or molecule, which gives the atom or molecule a net charge

ionization energy

the energy required to remove an electron from an atom or ion (abbreviation, IE)

electron affinity

the energy needed to remove an electron from a negative ion to form a neutral atom or molecule

cation

an ion that has a positive charge

anion

an ion with a negative charge

valence electrons

an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties

electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons