Unit 3: Periodicity Vocab-no images

period

A horizontal row of elements in the periodic table

Electronegativity

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

Ion

An atom or group of atoms that has a positive or negative charge due to losing or gaining electrons

Metals

Elements that are good conductors of electric current and heat, are malleable and ductile. On left side of periodic table.

Nonmetals

Elements that are poor conductors of heat and electric current, on right side of the periodic table.

Metalloids

Elements that have properties of both metals and nonmetals, the stair-step on the periodic table.

alkali metals

Group 1, 1 valence electron, very reactive, soft, silver, shiny, low density metals

Halogens

Group 17, 7 valence electrons, most reactive non-metals; also known as "halides"

alkaline earth metals

Group 2, 2 valence electrons, harder than the alkali metals and are also less reactive

transition metals

Groups 3-12, 1-2 valence electrons, less reactive than alkali-earth metals, shiny, good conductor of thermal energy and electrical current, high density metals

actinide series

Part of the inner transition metals following actinium in the periodic table, in which the 5f orbitals are being filled

lanthanide series

Part of the inner transition metals following lanthanum in the periodic table, in which the 4f orbitals are being filled

octet rule

States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons

ionization energy

The amount of energy required to remove an electron from an atom

Reactivity

The ease and speed with which an element combines, or reacts, with other elements and compounds.

Group

Vertical column in the periodic table

Anion

an ion with a negative charge due to gaining electrons

Cation

an ion with a positive charge due to losing electrons

inert/noble gases

group 18 gases, have 8 valence electrons and are stable and non-reactive

atomic radius

one-half the distance between the nuclei of identical atoms that are bonded together; ie. size of an atom

Group A elements

representative elements; Groups 1,2,13-18

Group B elements

transition metals; groups 3-12

periodic law

when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties