Question 1

Which of the following best explains why carbon dioxide ($$\mathrm{CO_2$}) is a $$nonpolar molecule, even though it contains polar bonds?

Accepted Answer

The molecule is linear, and the bond dipoles are equal and opposite, canceling each other.

Question 2

Which of the following molecules is polar due to its molecular geometry, despite having identical surrounding atoms?

Accepted Answer

$$\mathrm{PH_3$}$$

Question 3

A molecule has three electron groups and one lone pair on the central atom. What is its molecular shape and is it likely to be polar?

Accepted Answer

Bent; polar

Question 4

Which statement correctly describes a nonpolar molecule?

Accepted Answer

It can contain polar bonds, but the molecular shape causes the dipoles to cancel.

Question 5

Given the Lewis Dot structure for $$\mathrm{$$CCl_4$$}$$, what is the molecular geometry and polarity?

Accepted Answer

Tetrahedral; nonpolar

Question 6

Which of the following molecules is expected to be polar due to the presence of lone pairs on the central atom?

Accepted Answer

$$\mathrm{PH_3$}$$

Question 7

A student claims that $$\mathrm{F_2Se} is $$nonpolar because it contains only fluorine and selenium. Which concept best refutes this claim?

Accepted Answer

Molecular geometry and the presence of lone pairs can make a molecule polar even if all surrounding atoms are the same.

Question 8

Which of the following is a requirement for a molecule to be considered a 'perfect shape' and thus nonpolar?

Accepted Answer

All surrounding atoms must be the same and there must be no lone pairs on the central atom.

Question 9

Which molecule below is an example of a polar molecule due to its shape, even though all bonds are identical?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 10

A molecule has four electron groups and two lone pairs on the central atom. What is its molecular shape and is it polar or nonpolar?

Accepted Answer

Square planar; nonpolar

Question 11

Which of the following best describes the difference between a polar and a nonpolar molecule?

Accepted Answer

Polar molecules have unequal sharing of electrons and a net dipole moment.

Question 12

Which molecule is nonpolar due to its perfect tetrahedral shape and identical surrounding atoms?

Accepted Answer

$$\mathrm{$$CCl_4$$}$$

Question 13

If a molecule has a central atom with two lone pairs and two bonded atoms, what is its expected shape and polarity?

Accepted Answer

Bent; polar

Question 14

Which of the following molecules is most likely to be nonpolar?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 15

A molecule has a central atom with three bonded atoms and one lone pair. What is its molecular geometry and is it polar?

Accepted Answer

Trigonal pyramidal; polar

Question 16

Which of the following is true about the polarity of $$\mathrm{BCl_2F}$$?

Accepted Answer

It is polar because the surrounding atoms are not identical.

Question 17

Which factor is most important in determining whether a molecule is polar or nonpolar?

Accepted Answer

The molecular geometry and the electronegativity of the atoms.

Question 18

Which of the following molecules is polar due to the presence of lone pairs and a bent shape?

Accepted Answer

$$\mathrm{H_2O}$$

Question 19

A molecule has a central atom with no lone pairs and identical surrounding atoms. What is its expected polarity?

Accepted Answer

Nonpolar

Question 20

Which of the following best describes the effect of lone pairs on the central atom regarding molecular polarity?

Accepted Answer

Lone pairs on the central atom often create an asymmetrical shape, leading to a polar molecule.

Molecular Polarity and Perfect Shapes: Study Notes for GOB Chemistry

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