Sunday 7 May 2017

Chemistry 11

BIG UNIT 5 Review Assignment.  Answers to selected questions.

1.  Definitions:  You are on your own!  Make sure you know the difference between polar and non-polar covalent bonds as we didn't go over these in detail.

3.  In any energy level:  electrons are added in the following order:  s, p, d and f.

4a)  Protons=86      electrons=86       neutrons=136

4c)  Protons=92       electrons=92      neutrons=142

4e)  Protons=27        electrons=24      neutrons=631

5a) [Ar]4s23d10

5c) [Xe]6s24f145d106p2

h)  Mn+2= start with Mn=25 electrons.  [Ar]4s23d5        Take off 2 electrons.   So  it becomes [Ar]3d5   (electrons are removed from energy level 4 first).

7)  Masses are the periodic table are not whole numbers since the mass represents the average atomic mass of ALL the isotopes of that element.

8a)  Across a period on the table, atomic radius decreases since electrons are being added to the same energy level.   Protons are also added as you go across a period.  The attraction between protons and electrons increases as you go across a period, so the atoms "shrink" in towards the center.

9b) Down a group on the periodic table, ionization energy decreases since energy levels are being added with each new group.   Electrons are getting further from the nucleus and therefore getting easier to remove.

10)  We will discuss this one in class.

11a)  Rb has a larger radius than I since electrons are added to the same energy level as you move across.   It has more electrons and more protons pulling them in.

12a) Ne has greater ionization energy than Ar.  Ne has outer electrons which have a greater pull towards the nucleus.

13a) C= greater electronegativity.  Pull of its electrons is greater since it has less energy levels than Si.

14a)  P is more reactive than As.  P has greater attraction for electrons therefore can pull off electrons more easily from another element.

15) valence electrons are the most important in bond forming.

16)  We will go over some of these.

17a) non-polar covalent bond       17c) ionic bond          17e) covalent bond (non polar)