CHEM 219[ organic theory]
2025, latest mdl questions and
answers..*
On a piece of scratch paper, write out the Lewis Dot Diagram for each of the indicated elements
and determine the following for each:
a) The number of Lone Pairs the atom possesses in its valence shell.b) The number of Unpaired
Electrons the atom possesses in its valence shell.c) The number of bonds the atom will form.
Oxygen
Carbon
Hydrogen
Nitrogen - ANSWERS-Oxygen - a) 2 b) 2 c) 2
Carbon - a) 0 b) 4 c) 4
Hydrogen- a) 0 b) 1 c) 1
Nitrogen - a) 1 b) 3 c) 3
Classify the bonding between the given pairs of atoms as ionic, covalent, or polar covalent. Use
the table of electronegativities shown below to help with the classification.
a. Br and Br
b. K and Cl
c. P and Cl
, d. C and O
e. Na and Br - ANSWERS-a. Br-Br: Electronegativity difference () = 0 = COVALENT (or pure
covalent)
b. K-Cl: () = 2.2 = IONIC
c. P-Cl: ()= 0.9 = POLAR COVALENT
d. C-O: ()= 1.0 = POLAR COVALENT
e. Na-Br: () = 1.8 = POLAR COVALENT
Define the term constitutional isomer. - ANSWERS-Two (or more) different chemical compounds
with the same molecular formula but different connectivity between the atoms in their
structural formulae.
Explain (using specific evidence) what makes the following two compounds constitutional
isomers of one another: - ANSWERS-Both compounds have a MF of C3H6O - same MF.
Compound "a" has a 3-carbon chain with a C=O in the middle. No H atom connected to C of
C=O.
Compound "b" has a 3-carbon chain with a C=O at the end. There is an H attached to the C of
the C=O.
What is the relationship between the compounds shown? Are they the same compound,
constitutional isomers, or two different compounds that are not related to one another?
Explain. - ANSWERS-Different compounds that are not related. They have different MF - (a)
C3H8O, (b) C3H6O.
Identify each of the following carbon skeletons as linear (continuous), branched, or cyclic. -
ANSWERS-a) Branched
b) Linear (continuous)
c) Cyclic
2025, latest mdl questions and
answers..*
On a piece of scratch paper, write out the Lewis Dot Diagram for each of the indicated elements
and determine the following for each:
a) The number of Lone Pairs the atom possesses in its valence shell.b) The number of Unpaired
Electrons the atom possesses in its valence shell.c) The number of bonds the atom will form.
Oxygen
Carbon
Hydrogen
Nitrogen - ANSWERS-Oxygen - a) 2 b) 2 c) 2
Carbon - a) 0 b) 4 c) 4
Hydrogen- a) 0 b) 1 c) 1
Nitrogen - a) 1 b) 3 c) 3
Classify the bonding between the given pairs of atoms as ionic, covalent, or polar covalent. Use
the table of electronegativities shown below to help with the classification.
a. Br and Br
b. K and Cl
c. P and Cl
, d. C and O
e. Na and Br - ANSWERS-a. Br-Br: Electronegativity difference () = 0 = COVALENT (or pure
covalent)
b. K-Cl: () = 2.2 = IONIC
c. P-Cl: ()= 0.9 = POLAR COVALENT
d. C-O: ()= 1.0 = POLAR COVALENT
e. Na-Br: () = 1.8 = POLAR COVALENT
Define the term constitutional isomer. - ANSWERS-Two (or more) different chemical compounds
with the same molecular formula but different connectivity between the atoms in their
structural formulae.
Explain (using specific evidence) what makes the following two compounds constitutional
isomers of one another: - ANSWERS-Both compounds have a MF of C3H6O - same MF.
Compound "a" has a 3-carbon chain with a C=O in the middle. No H atom connected to C of
C=O.
Compound "b" has a 3-carbon chain with a C=O at the end. There is an H attached to the C of
the C=O.
What is the relationship between the compounds shown? Are they the same compound,
constitutional isomers, or two different compounds that are not related to one another?
Explain. - ANSWERS-Different compounds that are not related. They have different MF - (a)
C3H8O, (b) C3H6O.
Identify each of the following carbon skeletons as linear (continuous), branched, or cyclic. -
ANSWERS-a) Branched
b) Linear (continuous)
c) Cyclic
