COLUMNS - (__________)

Question

elements in the ______ column contain the _____ number of valence electrons and have ______ chemical properties.
valence electrons - the number of electrons in the _______ shell.
ROWS - (______________)
elements in the _________ row have the ________ number of energy levels.

Answer 1

COLUMNS - (GROUPS/FAMILIES)
elements in the SAME column contain the SAME number of valence electrons and have SIMILAR chemical properties.
valence electrons - the number of electrons in the OUTER shell.

ROWS - (PERIODS)
elements in the SAME row have the SAME number of energy levels.