Chapter 4: The Periodic Table - Chemistry

periodic law

periodic law

the law that states that the repeating physical and chemical properties of elements change periodically with their atomic number

valence electron

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

group

a vertical column of elements in the periodic table

period

a horizontal row of elements in the periodic table

main-group elements

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

alkali metal

one of the elements of Group 1 of the periodic table

alkaline-earth metal

one of the elements of group 2 of the periodic table

halogen

one of the elements of group 17 of the periodic table

noble gas

an unreactive element of group 18 of the periodic table that has 8 electrons in its outer level

transition metal

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

lanthanide

a member of the rare-earth series of elements whose atomic numbers range from 58 to 71

actinide

any of the elements of the actinide series which have an atomic number from 89 to 103

alloy

a solid or liquid mixture of two or more metals

reactivity

how likely an atom is to interact (react) with other atoms

ionization energy

the energy required to remove an electron from an atom or ion

electron shielding

the reduction of the attractive force between a positively charged nucleus and its outermost electrons due to the cancellation of some of the positive charge by the negative charges of the inner electrons

bond radius

half the distance from center to center of two like atoms that are bonded together

electronegativity

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

electron affinity

energy released when an electron is added to a neutral atom

nuclear reactions

a reaction that affects the nucleus of an atom

superheavy element

an element whose atomic number is greater than 106

Transuranium element

element with an atomic number greater than 92

transmutation

1 nucleus is changed into a different nucleus