113ch7periodictrends

113ch7periodictrends - CHAPTER 7 SUMMARY NOTES ON PERIODIC...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CHM 113 – Dr. Ron Briggs Periodic Trends (Ch. 7) 1 CHAPTER 7 – SUMMARY NOTES ON PERIODIC TRENDS VALENCE ELECTRONS (VE) = Electrons that reside in the outermost shell of the atom. Trend in Valence Electrons: # of valence electrons = group number on the periodic table halogens = 7 VE oxygen, sulfur = 6 VE sodium, potassium = 1 VE noble gases = 8 VE EFFECTIVE NUCLEAR CHARGE (Z EFF ) = The net positive charge that an electron “sees” from the nucleus Trends in Z eff experienced by outer shell electrons: Increase from left to right (across a row) - # of core electrons (and shielding) stays the same, but the number of protons increases Increase (slightly) from top to bottom (down a group) - (Z-S) is the same down a group, but larger electron cores don’t shield as well ATOMIC RADIUS (Size) = The distance from the center of the nucleus to the outermost electron in an atom Trends in atomic radius: Increase from right to left - Decrease in Z eff means less attraction of the outer electrons to the nucleus Increase from top to bottom - Filling higher shells that are farther from the nucleus For Ions: Cations are smaller than their parent atoms - When valence electrons are removed, the remaining electrons are drawn in closer by the protons in the nucleus Anions are larger than their parent atoms - When valence electrons are added, they drift farther from the nucleus since the protons in the nucleus are no longer enough to suck them all in as far Ions of the same charge follow the normal trend (increase R L, T B) - S 2- is larger than O
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

113ch7periodictrends - CHAPTER 7 SUMMARY NOTES ON PERIODIC...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online