U6L3 - Lecture Notes - Molecular Structures

Multiple Choice

Which molecular model is one of the most useful and it uses letter symbols and bonds to show relative positions of atoms?

• ball-and-stick

• molecular model

• structural formula

• space-filling molecular model

Match

Match the name of the model at left with the letter at right of its representation of phosphorus trihydride (phosphine) in the figure.

• Molecular formula

• Lewis structure

• space-filling model

• structural model

• ball-and-stick

A

B

c

D

E

• A

• B

• c

• D

• E

Reorder

Place the steps used for drawing Lewis structures in the correct order from beginning to end.

• Predict the location of the central atom and hydrogen atoms.

• Determine the number of electrons available for bonding.

• Determine the number of bonding pairs.

• Place the bonding pairs.

• Determine the number or electron pairs remaining.

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Multiple Select

Which statements correctly describe how to draw a Lewis structure?

Multiple select question.

• The atom with the highest group number is usually the central atom.

• Lone pairs of electrons do not need to be included in the structure.

• A Lewis structure includes all the valence electrons in the species.

• A single bond contains two electrons and is represented by a solid line.

Multiple Choice

Why are resonance structures used when drawing the nitrate ion?

• The placement of atoms of elements can change.

• Equivalent structures can be used to represent the ion.

• The number of atoms of elements can change.