Transcript Periodic Table & Electrons

Periodic Table & Electrons
• Valence Electrons – electrons that
are in the highest energy level of an
atom.
• Example: Silicon
• 1s2 2s2 2p6 3s2 3p2
• 4 valence electrons…
Periodic Table & Electrons
• Representative
elements (groups 1,
2, 13-18)
• Valence electrons =
last number in the
group number.
• Silicon Group 14 =
4 valence e- !
[http://academic.reed.edu/chemistry/roco/Lewis/images/periodic.gif]
Periodic Table & Electrons
• Noble gases
have 8 valence
electrons.
• This property
makes them
inert, or
unreactive.
Neon = 1s22s22p6
Periodic Table & Electrons
• Other atoms form ions so that they
have 8 electrons in the highest level.
[http://home.att.net/~cat6a/images/form_Na_ion.jpg]
[http://www.chemprofessor.com/ptable4.gif]
Ionization Energy
• The energy needed to remove an
electron from an atom.
[http://www.iun.edu/~cpanhd/C101webnotes/modern-atomic-theory/images/ionization-energy.jpg]
[http://www.chemistry.ohio-state.edu/~grandinetti/teaching/Chem121/lectures/periodic%20trends/ionization_table.JPG]
Ionization Energy
• There are also 2nd Ionization
Energies (remove 2nd electron)
and 3rd Ionization Energies
(remove 3rd electron).
• Pg. 180
Electronegativity
• The measurement of how much
an atom “attracts” extra
electrons.
Atomic Radius
• Distance from the center of an
atom to the outermost electron.
• Ba, Ca, Sr
[http://wps.prenhall.com/wps/media/objects/602/616516/Media_Assets/Chapter05/Text_Images/FG05_20-07UN.JPG]
[http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/1e67a7ad.gif]