electrons in the highest occupied energy level

# of the group = # of valence electrons determines the chemical properties of an

element usually the only electrons used in chemical

bonds

http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_27-06un.JPG

when forming compounds, atoms tend to achieve the electron configuration of a noble gas (ns2np6) atoms of metallic elements lose electrons

producing cations (positive ions) Ca becomes Ca2+

name of ion is the same atoms of nonmetallic elements gain

electrons producing anions (negative ions) Cl becomes Cl1-

name of ion is now chloride instead of chlorine

for transitional metals, charges of cations may vary iron can be Fe2+ or Fe3+

other elements fill some orbitals but don’t quite get a noble gas electron configuration

http://jade.ccccd.edu/mweis/Images/Fireworks%20Drawings/2401%20related%20drawings/drawings%20in%20fireworks/body,%20cell,%20tissue/body_chem/chem_drw_atom_generic.png

electron dot structures/diagrams are used to show valence electrons each dot around the element symbol

represents a valence electron

  ...etc.

As it turns out, atoms bond together for a very simple reason: atoms like

to have full valence shells.

1+ 2+ 3-3+ 4+/- 2- 1- 0

+ +- -

e-

it is easier to just draw Lewis-dot structures to show valence electrons instead of the drawing the whole atom

http://images.google.com/imgres?imgurl=http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/imgper/econfig.gif&imgrefurl=http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/perlewis.html&h=267&w=512&sz=22&tbnid=__EXctBwlG0J:&tbnh=66&tbnw=128&hl=en&start=1&prev=/images%3Fq%3DElectron%2BDot%2BDiagrams%26svnum%3D10%26hl%3Den%26lr%3D

http://www.iun.edu/~cpanhd/C101webnotes/chemical-nomenclature/images/polyions.jpg