Periodic Table: Periods: Are the horizontal rows on the Periodic Table. All elements in the same period contain the same number of energy levels. Valence electrons: Electrons in the outermost energy level of the atom. The number of valence electrons increases by one across a period.

Periodic Table: Groups-A number = # of valence electrons Ex. Elements in group 1A – contain 1 valence e- Elements in group 3A – contain 3 valence e- Elements in group 7A – contain 7 valence e-

Metals, Nonmetals, and Metalloids

Periodic Table: Metals – Located on the left side of the stair-step line (they are solids, except Mercury which is liquid) Nonmetals– Located on the right side (solids, liquids, or gases). Metalloids: Located between metals & nonmetals (touching the stair-step line).

Periodic Table: Groups: Vertical columns (elements in the same group have similar properties). Group 1A: The most reactive metals (Alkali metals). Group 2A : Reactive metals also (Alkaline Earth metals). Group 7A: The most reactive non metals (Halogens). Group 8A: Unreactive, very stables. (Noble gases).

Periodic Table: The Periodic Table is divided into four different blocks: 1) s-block: Its valence electrons occupy only “s” orbitals. s-block: Group 1A & 2A

Periodic Table: 2) p-block: The outermost electron occupy “p” orbitals. p-block: Group 3A - 8A

Periodic Table: s-block Representative or group A elements p-block

Periodic Table: 3) d-block: They have a filled outermost “s” orbital & partially filled or filled “d” orbitals in energy level (n-1). d-block: Groups B, the transition metals

Periodic Table: 4) f-block: The outermost electron is placed in “f” orbitals. f-block: The inner transition metals

Periodic Table (Blocks): “s” block “p” block “d” block Representative Representative Transition Metals “f” block Inner Transition Metals

Classification of Groups: