Question 1

Which of the following statements best describes the trend of electronegativity across the periodic table?

Accepted Answer

Electronegativity increases from left to right across a period and increases from bottom to top of a group.

Question 2

Given the electronegativity values: $$\mathrm{O} = 3.5$$, $$\mathrm{Cl} = 3.0$$, what type of bond is formed between oxygen and chlorine?

Accepted Answer

Polar covalent

Question 3

Which molecule is nonpolar despite having polar bonds due to its symmetrical shape?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 4

A bond between potassium ($$\mathrm{K}$$, electronegativity $$= 0.8) $$and chlorine ($$\mathrm{Cl}$$, electronegativity $$= 3.0) $$would be classified as:

Accepted Answer

Ionic

Question 5

Which intermolecular force is primarily responsible for the high boiling point of water?

Accepted Answer

Hydrogen bonding

Question 6

What is the molecular shape of $$\mathrm{CH_4$}$$ according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 7

Which of the following molecules would exhibit only dispersion forces as the main type of intermolecular attraction?

Accepted Answer

$$\mathrm{Br_2$}$$

Question 8

A molecule has a central atom with three electron groups and no lone pairs. What is its molecular geometry and bond angle?

Accepted Answer

Trigonal planar, $$120^\circ$$

Question 9

Which of the following best explains why $$\mathrm{NH_3$} is a $$polar molecule?

Accepted Answer

It has polar bonds and a trigonal pyramidal shape, so dipoles do not cancel.

Question 10

Which of the following compounds would you expect to be a solid at room temperature due to strong attractive forces?

Accepted Answer

$$\mathrm{NaCl}$$

Question 11

If the electronegativity difference between two atoms is $$2.5$$, what type of bond will they most likely form?

Accepted Answer

Ionic

Question 12

Which of the following molecules has a bent shape due to lone pairs on the central atom?

Accepted Answer

$$\mathrm{H_2O}$$

Question 13

Which of the following is true about hydrogen bonds?

Accepted Answer

They occur when hydrogen is bonded to highly electronegative atoms like O, N, or F.

Question 14

Which of the following best describes the electron sharing in a polar covalent bond?

Accepted Answer

Electrons are shared unequally between atoms.

Question 15

A molecule of $$\mathrm{CF_4$}$$ has polar bonds but is nonpolar overall. Why?

Accepted Answer

The molecule is tetrahedral and the dipoles cancel due to symmetry.

Question 16

Which of the following molecules would have dipole-dipole attractions as the main intermolecular force?

Accepted Answer

$$\mathrm{HBr}$$

Question 17

Which of the following best describes the separation of charges in a polar bond?

Accepted Answer

The bond has a dipole, with partial positive and negative ends.

Question 18

Which of the following is the strongest type of intermolecular force?

Accepted Answer

Ionic bonds

Question 19

Which of the following molecules is polar due to its shape and bond polarity?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 20

A student claims that $$\mathrm{Cl_2$} is a $$polar molecule because it contains two chlorine atoms. What is the best explanation for why this claim is incorrect?

Accepted Answer

The bond between two chlorine atoms is nonpolar because the electronegativity difference is zero.

Electronegativity, Bond Polarity, and Molecular Structure

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