Bell Work 11/3/15 Sit with your assigned group Power up laptop and go to class website www.mrssoisson.weebly.com Read over the Periodic Trends Packet

Goals for Today Research property Discover and explain the periodic trend. Create a poster. Share your findings with two groups (answer questions 1 through 7) Groups 1,2,3 will share with each other Groups 4,5,6 will share with each other

Your Grade for Today Actively support your group Every student contributes to presentation Poster contains the following items Your group’s names and class period Identify Trend Element Symbols and values in the squares Units for property specified Arrow on the side showing increasing trend Arrow on the top showing increasing trend (See example at the front)

Bell work 11/5/15 Sit with your group Spend 5 minutes discussing: Format of your presentation Determine who will say what Name of property you researched Definition of property Answer questions 1-7 Horizontal trend Direction of arrow Vertical trend Highest Lowest Why this trend occurs (both horizontal and vertical)

Periodic Trends Summary Notes Periodic table unit Periodic Trends Summary Notes

Important Trends Electronegativity- ability of an atom to attract electrons and form a chemical bond Increases moving up the group Increases left to right across a period Noble Gas family has 0 electronegativity

Electronegativity Increases Increases

Why does this trend exist? Going down a family, the _____________ increase. The positively charged ________ of smaller elements with fewer energy levels can more easily ________ electrons. Going across a period, valence electrons __________ and the atom gets closer to achieving an ______. Thus, the elements on the right side more easily _______ electrons. The noble gases have ____ electronegativity because they already have __ electrons (full octet).

Practice Which element is more electronegative? F or Be Sn or Si Ni or Cr Cs or Br

Important trends Ionization Energy- the energy needed to remove an electron Creates an ion The number of protons and electrons are no longer equal. Increases moving up the group Increases left to right across a period

Ionization energy Increases Increases

Why does this trend exist? Going down a family, the _____________ increase. The positively charged ________ is farther away from the __________ electrons. Thus, it take less ________ to remove an electron. As you go across a period, the number of valence electrons ________, with elements on the right side closer to having an ______. The energy required to remove an electron from potassium (with ___ valence electron) is _____ than the energy to remove an electron from bromine (which has ______ valence electrons).

Practice Circle the element that has the greater ionization energy Zr or Sn S or Cl Cs or Ba C or Ne

Important periodic Trends Atomic Radii- distance from the nucleus to the outermost stable electron Trend: Increases moving down the groups Decreases right to left across the periods

Atomic Radius

Why does this trend exist? As you go down a family, there are more _____________. More ____________ leads to an atom with a larger _____. The valence electrons of all elements in a period are in the same ___________. As you go across a period, one more _______ is added. That one extra ____________ charged proton pulls the electrons in a little ______ making the radius a bit _________ across the period.

Atomic Radius Increases Increases

Practice Which element has the larger atomic radius? Fe or Ni F or N Ne or Br C or F

Important Trends Ionic Radii- distance from the nucleus to the outermost electron in an ion Increases moving down a family As you go across a period from right to left, the trend varies. Ask yourself, “What Noble Gas does it become? The noble gas further down the periodic table has the higher ionic radius

Why does this trend occur? As you go down a family, there are more ____________. More __________ leads to an atom with a larger _____. As you go across a period, the ionic radius can ____. To compare two ____ in the same period, determine which _________ they will become. The ion which becomes a noble gas further ____ the periodic table would have the ______ ionic radius.

Practice Which element has the larger ionic radius? Cl- or Br- O2- or Ca2+ B3+ or S2- K+, Ca 2+, Ga3+

Summary Which properties trend in the same way?