Supplemental Instruction
Iowa State University / Leader: / Grady
Course: / Chem 177
Instructor: / Kingston
Date:
1)Rank the following in size smallest to largest:
S2-Cl-ArK+Ca2+
Ca2+K+ArCl-S2-
2)What is the least electronegative atom?
a)Fr
b)F
c)H
d)Rn
3)What trends INCREASE together?
- Size
- Electro negativity
- First Ionization Energy
a)I and III
b)I, II, and III
c)II, III
d)None of the above
4)Which is not true about metals?
a)They usually have high densities
b)They tend to lose electrons
c)They conduct electricity well but don’t conduct heat very well
d)They same electron affinities close to 0
5)What is the difference…
a)between ionic and covalent?
Change in electronegativity more than 2 is ionic (metal and nonmetal)
b)Between polar and nonpolar?
Both are covalent but non polar is a change in electronegativity less than .3
6)Sulfur has ____10___ core electrons and ____6___valence electrons. If it bonds with 4 Bromine it has_5___ electron domains. It’s molecular geometry is __sawhorse__ while its electron geometry is _triganolbipyramidal_with bond angles of ____~120 and ~90___.
7)Which are acceptable resonance structures of SiNO-?
a)Only I
b)Only II
c)I and III
d)I and II
e)I, II and III
8)Which of the above resonance structures is the BEST one for SiNO-?
The second one because the formal charge of -1 is on Oxygen the most electronegative atom
9)Draw a lewis diagram and the resonance structures for ozone. Assign all formal charges also.
a)What is molecular geometry?
bent
b)What is the bond angle and is it polar or non polar?
<120 and polar
c)What is the average bond order for Oxygen bonds?
1.5
10)Calculate the enthalpy for the reaction
H-N / 391N-N / 163
N=N / 418
N=N / 945
O-H / 463
O=O / 498
2N2H2 + O22H2O + N2
2(418) + 4(391) – 4(463) – 1(945)
∆H = -397 kJ
11)Which bond is polar covalent?
a)C-H
b)Li-Br
c)O=O
d)N-F
12)Draw the resonance structures for the following:
a)SO2
b)
13)Draw lewis structures for the following a) Li b) Ba2+ c) C d) Cl-