CJ Bianconi
Chem 102
Spring 2015
Mock Half Exam Key
1. Electronegativity increases as you go up and right on the Periodic Table.
2. A place where amplitude is 0 is called a node.
3. A cation has (more/less) electrons than the neutral atom while an anion has (more/less)
electrons than the neutral atom.
4. The 4th shell has 4 (#) subshells and 16 (#) orbitals.
5. A 5d subshell can hold 10 (#) electrons.
6. Arsenic (As) has 2 (#) 4s electrons, 0 (#) 4d electrons, and 3 (#) 4p electrons.
7. A central atom with a steric number of 4 will have bond angles of 109.5°.
8. If a molecule has linear geometry, the central atom will have 2 (#) hybridized subshells
that are labeled sp.
9. When two electrons form a bond, the amplitudes of their waves are added together by the
process called constructive interference.
10. Atoms prefer to have 8 (#) (valence) electrons around them according to the octet rule.
True/False
11. ( T / F ) Sigma bonds are only found in single bonds.
12. ( T / F ) Carbon always has sp3 hybrid orbitals used in sigma bonding.
13. ( T / F ) A filled 5d subshell will have 5 electron pairs in it.
14. ( T / F ) A filled p orbital has 1 electron exclusively on the positive amplitude side and 1
electron exclusively on the negative amplitude side.
15. ( T / F ) A compound with 3 atoms always has linear geometry.
16. ( T / F ) Sigma bonds allow free rotation of the participating atoms.
17. ( T / F) A bromide (Br -) ion has one half-filled orbital.
18. ( T / F ) UV light has lower wavelength than X-rays
19. ( T / F ) Steric number counts single, double, and triple bonds equally.
20. ( T / F ) The amplitude of a wave determines its energy.
21. Above is the structure for the chemical dopamine. How many pi bonds are in this
molecule? How many sigma bonds are there?
There are 3 pi bonds and 22 sigma bonds.
22. What is the hybridization for the atoms marked with a 1, 2, and 3? What are the bond
angles for the hybridized orbitals?
Atom 1: C (sp2), bond angles of 120°
Atom 2: C (sp3), bond angles of 109.5°
Atom 3: H (1s) (no hybridization), bond angle of 360°
23. Draw the Lewis Dot Structure for Nitrogen gas (N2). Symbolically represent all bonds in
the element by detailing whether they are sigma or pi bonds, and listing the orbitals used
in the bonds.
σ: N (sp) + N (sp)
π: N (2px) + N (2px)
π: N (2py) + N (2py)
24. Draw the electromagnetic spectrum and label the directions of energy, wavelength, and
frequency.
25. Draw the orbital diagram for ground-state oxygen, then draw oxygen’s orbital diagram
when it is sp2 hybridized.
26. According to Valence Bond Theory, bonds are formed by:
Bonds are formed by the constructive interference of overlapping half-filled orbitals on
neighboring atoms.
27. Draw the Lewis Dot Structure of CH3OH and identify any net dipole on the molecule.
What is the predominant IMF expressed by this molecule?
Net dipole with negative end on the right side, positive end on the left
Predominant IMF is HB
28. Draw the Lewis Dot Structure of CHCl3 and identify any net dipole on the molecule.
What is the predominant IMF expressed by this molecule?
Net dipole with negative end on left side, positive end on the right
Predominant IMF is DD
29. Draw the Lewis Dot Structure of C6H14 and identify any net dipole on the molecule.
What is the predominant IMF expressed by this molecule?
No net dipole on molecule
Predominant IMF is LDF
30. Draw a diagram of two molecules that shows a momentary dipole occurring.
31. Draw a diagram of two molecules that shows a dipole-dipole interaction occurring.
32. Complete this chart:
# of e- directions in
space
hybridization
# of unhybridized p
orbitals
electron pair
geometry
2
sp
2
linear
3
sp2
1
trigonal planar
4
sp3
0
tetrahedral
5
sp3d
0
trigonal bipyramid
6
sp3d2
0
octahedral
33. Symbolically represent all of the bonds in C2H3Cl.
3 σ: C (sp2) + H (1s)
σ: C (sp2) + C (sp2)
σ: C (sp2) + Cl (sp3 OR 3pz)
π: C (2px) + C (2px)
34. Symbolically represent all of the bonds in HCN.
σ: C (sp) + N (sp OR 2pz)
σ: C (sp) + H (1s)
π: C (2px) + N (2px)
π: C (2py) + N (2py)
35. Symbolically represent all of the bonds in CO2.
2 σ: C (sp) + O (sp2 OR 2px)
π: C (2py) + O (2py)
π: C (2pz) + O (2pz)
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CJ Bianconi Chem 102 Spring 2015 Mock Half Exam Key