P.1.2

entire row at the top end of the table

the rows at the bottom of the table that connect two sections

the column at the far left of the table

the second column from the right of the table

Elements are arranged from fewest protons to most protons.

Elements are arranged from most protons to fewest protons.

Elements are arranged from fewest neutrons to most neutrons.

coal

oxygen

lithium

elements in the same group

elements in the same period

elements with similar atomic masses

atomic radius increases

attraction for electrons increases

attraction for electrons decreases

They are radioactive.

They have complete outer energy levels.

They have the highest atomic masses of any elements.

They have only one electron in their outer energy level.

by the color and shape of the elements

by the number of electrons in the elements

by the group in which the elements are located

metals

nonmetals

metalloids

noble gases

density

reactivity

specific heat

melting point

neon (Ne) and radon (Rn)

fluorine (F) and bromine (Br)

silicon (Si) and phosphorous (P)

sodium (Na) and magnesium (Mg)