Question 1

Which of the following best explains why the atomic radius increases as you move down a group in the periodic table?

Accepted Answer

Electron shielding increases, reducing the effective nuclear charge felt by outer electrons.

Question 2

Chromium(III) oxide is used as a pigment known as 'hospital green.' What is the correct chemical formula for chromium(III) oxide?

Accepted Answer

$$\mathrm{Cr_2O_3}$$

Question 3

Which of the following molecules has a trigonal planar molecular geometry according to VSEPR theory?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 4

A molecule of carbon dioxide ($$\mathrm{CO_2$}) is $$described as linear. Which of the following best explains this shape?

Accepted Answer

The central carbon atom has two electron sets that arrange themselves as far apart as possible, resulting in a bond angle of $$180^\circ.$$

Question 5

Which of the following statements about electron shielding is correct?

Accepted Answer

Electrons between the nucleus and the electron of interest reduce the effective nuclear charge felt by the electron of interest.

Question 6

Draw the Lewis structure for $$\mathrm{NO_2$}$$ and determine the number of valence electrons in the molecule.

Accepted Answer

17 valence electrons

Question 7

Which of the following best describes the molecular geometry of ammonia ($$\mathrm{NH_3$}$$)?

Accepted Answer

Trigonal pyramidal

Question 8

Which of the following is a correct step in drawing a Lewis structure for a polyatomic molecule?

Accepted Answer

Count the total number of valence electrons, including any charge on the ion.

Question 9

Nitrogen dioxide ($$\mathrm{NO_2$}) is a $$major air pollutant. Which of the following is a primary source of $$\mathrm{NO_2$} in $$the environment?

Accepted Answer

Catalytic converters in cars

Question 10

Which of the following molecules is correctly matched with its molecular geometry?

Accepted Answer

$$\mathrm{CH_4$}$$ – Tetrahedral

Question 11

Which of the following best explains why electronegativity generally increases across a period from left to right?

Accepted Answer

The effective nuclear charge increases, pulling electrons closer to the nucleus.

Question 12

A molecule of $$\mathrm{SO_2$}$$ has what molecular shape according to VSEPR theory?

Accepted Answer

Bent

Question 13

Which of the following is the correct Lewis structure for carbon dioxide ($$\mathrm{CO_2$}$$)?

Accepted Answer

$$\mathrm{O=C=O}$$ with each O having two lone pairs

Question 14

Which of the following molecules would you expect to have the largest bond angle?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 15

Which of the following is a correct application of the octet rule when drawing Lewis structures?

Accepted Answer

Hydrogen atoms should have two electrons in their valence shell.

Question 16

Which of the following best describes the effect of lone pairs on molecular geometry?

Accepted Answer

Lone pairs occupy more space than bonding pairs, reducing bond angles between atoms.

Question 17

Which of the following is the correct order of steps for drawing a Lewis structure for a compound?

Accepted Answer

Count valence electrons, sketch skeletal structure, place lone pairs on outer atoms, add remaining electrons to central atom, form multiple bonds if needed.

Question 18

Which of the following molecules is an example of a molecule with a tetrahedral geometry?

Accepted Answer

$$\mathrm{CH_4$}$$

Question 19

Which of the following best describes the relationship between atomic radius and electronegativity?

Accepted Answer

As atomic radius increases, electronegativity decreases.

Lecture 10: Chemical Bonding, Lewis Structures, and Molecular Shapes: Introductory Chemistry Study Notes

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