$\text{Formal charge} = \text{valence electrons} - \text{bonds} - \text{nonbonding electrons}$

Question 1

Which of the following elements is most likely to form four covalent bonds in organic molecules due to its tetravalency?

Accepted Answer

Carbon

Question 2

According to the octet rule, which of the following atoms is LEAST likely to obey the rule in its common compounds?

Accepted Answer

Aluminum

Question 3

What is the formal charge on the nitrogen atom in the nitrate ion $\mathrm{NO_3^-}$?

Accepted Answer

$0$

Question 4

Which principle states that electrons fill the lowest energy orbitals first?

Accepted Answer

Aufbau Principle

Question 5

Given the electron configuration $1s^2\ 2s^2\ 2p^5$, which element is this?

Accepted Answer

Fluorine

Question 6

Which of the following molecules is nonpolar due to its symmetrical geometry, despite having polar bonds?

Accepted Answer

Carbon dioxide ($\mathrm{CO_2}$)

Question 7

What is the correct electron configuration for the oxygen atom?

Accepted Answer

$1s^2\ 2s^2\ 2p^4$

Question 8

Which of the following statements about electronegativity is TRUE?

Accepted Answer

Electronegativity increases from left to right across a period.

Question 9

How many lone pairs are present on the central atom in the Lewis structure of ammonia ($\mathrm{NH_3}$)?

Accepted Answer

1

Question 10

Which of the following is the correct formula for calculating formal charge?

Accepted Answer

$	ext{Formal charge} = 	ext{valence electrons} - 	ext{bonds} - 	ext{nonbonding electrons}$

Question 11

Which atom is the most electronegative according to the Pauling scale?

Accepted Answer

Fluorine

Question 12

In the Lewis structure for $\mathrm{H_2O}$, how many bonding pairs and lone pairs are present on the oxygen atom?

Accepted Answer

2 bonding pairs, 2 lone pairs

Question 13

Which of the following best explains why water ($\mathrm{H_2O}$) is a polar molecule?

Accepted Answer

It has a bent geometry and a difference in electronegativity between H and O.

Question 14

Which rule states that every orbital in a subshell is singly occupied before any orbital is doubly occupied?

Accepted Answer

Hund's Rule

Question 15

What is the charge on the carbon atom in the cyanide ion ($\mathrm{CN^-}$)?

Accepted Answer

$0$

Question 16

Which of the following is a correct statement about the role of electrons in chemical bonding?

Accepted Answer

Electrons take part in chemical bonding.

Question 17

Which of the following elements is most likely to expand its octet in compounds?

Accepted Answer

Aluminum

Question 18

If a molecule has a formal charge of $-1$, what adjustment should be made when drawing its Lewis structure?

Accepted Answer

Add one electron to the total count

Question 19

Which of the following best describes the difference between a bonding pair and a lone pair in a Lewis structure?

Accepted Answer

A bonding pair is shared between two atoms; a lone pair belongs to one atom.

Question 20

Which of the following is the correct order of increasing electronegativity for the elements: C, N, O, F?

Accepted Answer

C < N < O < F

Atomic Structure, Bonding, and Electronegativity in Organic Chemistry

Study Guide - Practice Questions