DAILY QUESTION October 3, Group 18 on the periodic table is commonly referred to as the “____________”.

Agenda10/3/08 Daily Question Chapter 4 Section 3 Notes Assignments: 1. No assignment tonight.

Elements Classified into three groups: –Metals –Nonmetals –Semiconductors or Metalloids

Metals All metals: –Conduct heat and electricity Most metals: –Stretched and shaped

Alkali Metals Group 1 of the periodic table Soft, Shiny, and reacts violently with water Very reactive because they have only 1 valence electron Forms positive ions with a 1+ charge Found as compounds in nature Examples: –Sodium

Alkaline-earth Metals Group 2 of the periodic table Less reactive because they only have 2 valence electrons Form positive ions with a 2+ charge Form compounds with other elements Examples: –Calcium –Magnesium

Transition Metals Groups 3 – 12 of the periodic table Less reactive yet, but can lose electrons Form positive ions Examples: –Gold, Silver, Platinum, Copper, Iron, Cobalt, Manganese, Mercury

Radioactive Elements Nuclei of their atoms are continually decaying to produce different elements –Examples: Technetium and promethium Used to diagnose cancer, ingredients in glow-in-the-dark paints

Nonmetals Some elements in Group 13 – 16 and all the elements in Groups 17 and 18 Form many compounds Form negative ions

Halogens Group 17 on the periodic table Very reactive Form negative ions –Fluorine –Chlorine –Bromine –Iodine –Astatine

Noble Gases Group 18 of the periodic table Exist as single atoms instead of as molecules Inert, unreactive because s and p orbitals are full of electrons Do not form ions, do not form compounds –Helium, Neon, Argon, Krypton, Xenon, Radon

Semiconductors or Metalloids Only six elements are metalloids: –Boron, Silicon, Germanium, Arsenic, Antimony, and Tellurium Classified as nonmetals Are able to conduct heat and electricity