Question 1

Which of the following best describes how an atom 'owns' electrons when determining octet electrons?

Accepted Answer

An atom owns every lone electron it has and one electron for every bond it has.

Question 2

Given the Lewis structure for methane ($$\mathrm{CH_4$}$$), how many octet electrons does the central carbon atom own?

Accepted Answer

$$8$$

Question 3

Which element from the second row of the periodic table prefers to form three bonds and have one lone pair in its most stable state?

Accepted Answer

Nitrogen ($$\mathrm{N})$$

Question 4

How many valence electrons are present in ethene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

$$14$$

Question 5

Which of the following molecules does NOT satisfy the octet rule for all atoms?

Accepted Answer

Boron trifluoride ($$\mathrm{BF_3$})$$

Question 6

If an oxygen atom in a molecule has two bonds and two lone pairs, how many octet electrons does it own?

Accepted Answer

$$8$$

Question 7

Which of the following statements about bonding preferences is correct?

Accepted Answer

Carbon prefers to form four bonds and have no lone pairs.

Question 8

A molecule of formaldehyde ($$\mathrm{CH_2O}) is $$shown below. How many electrons does the central carbon atom own?

$$\mathrm{H_2C=O}$$

Accepted Answer

$$8$$

Question 9

Which of the following best explains why boron often forms compounds that do not satisfy the octet rule?

Accepted Answer

Boron is in group 3A and prefers to form three bonds, resulting in only six electrons around it.

Question 10

Which of the following is the correct number of valence electrons for nitrogen ($$\mathrm{N}$$)?

Accepted Answer

$$5$$

Question 11

In the molecule carbon dioxide ($$\mathrm{CO_2$}$$), how many bonds does each oxygen atom form with the central carbon atom?

Accepted Answer

Two

Question 12

Which of the following best describes the relationship between group number and bonding preference for second-row elements?

Accepted Answer

The group number minus two equals the number of bonds the element prefers to form.

Question 13

Which of the following molecules is most likely to be the least stable based on octet electron ownership?

Accepted Answer

Boron trifluoride ($$\mathrm{BF_3$})$$

Question 14

How many lone pairs does a fluorine atom have in its most stable state?

Accepted Answer

Three

Question 15

Which of the following is true for the bonding preference of oxygen?

Accepted Answer

Oxygen prefers to form two bonds and have two lone pairs.

Question 16

A molecule contains a central atom with three bonds and one lone pair. Which element is most likely the central atom?

Accepted Answer

Nitrogen

Question 17

Which of the following best describes the octet rule?

Accepted Answer

Atoms are most stable when they have eight electrons in their valence shell.

Question 18

How many valence electrons does a molecule of water ($$\mathrm{H_2O}) $$have?

Accepted Answer

$$8$$

Question 19

Which of the following is a correct statement about lone pairs and bonding pairs in the context of octet electrons?

Accepted Answer

Each lone pair counts as two electrons owned by the atom.

Question 20

Which of the following molecules has a central atom that does NOT satisfy the octet rule?

Accepted Answer

Boron trifluoride ($$\mathrm{BF_3$})$$

Bonding Preferences and the Octet Rule in Organic Chemistry

Study Guide - Practice Questions