Question 1

Which of the following best describes the purpose of drawing Lewis Dot Structures for ions and molecules?

Accepted Answer

To visualize the arrangement of valence electrons and predict bonding.

Question 2

When drawing the Lewis Dot Structure for the ion $$NH_4$$^+$$, what is the total number of valence electrons you should use?

Accepted Answer

8 - 1 = 7

Question 3

In the Lewis Dot Structure for $$ClO_3$$^-$$, which atom is typically placed at the center of the structure?

Accepted Answer

Chlorine

Question 4

Which rule is followed to ensure that atoms (except hydrogen) achieve a stable electron configuration in Lewis Dot Structures?

Accepted Answer

Octet Rule

Question 5

What is the correct number of valence electrons to use when drawing the Lewis Dot Structure for $$SO_4$$^{2-}$$?

Accepted Answer

$$6 + (4 	imes 6) + 2 = 32$$

Question 6

Why are brackets placed around the Lewis Dot Structure of polyatomic ions?

Accepted Answer

To show that the structure is an ion and to indicate its charge.

Question 7

Which of the following steps is performed LAST when drawing a Lewis Dot Structure for an ion?

Accepted Answer

Placing the structure in brackets and assigning the charge.

Question 8

A student draws the Lewis Dot Structure for $$PO_4$$^{3-}$$ and uses 28 valence electrons. What mistake did the student most likely make?

Accepted Answer

They forgot to add the electrons for the negative charge.

Question 9

Which of the following ions would require you to add two extra electrons to the total valence electron count when drawing its Lewis Dot Structure?

Accepted Answer

$$SO_4$$^{2-}$$

Question 10

In a Lewis Dot Structure, which element is most likely to violate the octet rule by having more than eight electrons around it?

Accepted Answer

Chlorine

Question 11

Which of the following best explains why hydrogen is only surrounded by two electrons in Lewis Dot Structures?

Accepted Answer

Hydrogen only needs two electrons to achieve the electron configuration of helium.

Question 12

A chemist is drawing the Lewis Dot Structure for $$NH_4$$^+$$. Which of the following is the correct step for accounting for the positive charge?

Accepted Answer

Subtract one electron from the total valence electrons.

Question 13

Which of the following is a correct application of the octet rule in the Lewis Dot Structure for $$ClO_3$$^-$$?

Accepted Answer

Each oxygen atom is surrounded by eight electrons.

Question 14

When drawing the Lewis Dot Structure for $$SO_4$$^{2-}$$, what is the correct total number of valence electrons to use?

Accepted Answer

$$6 + (4 	imes 6) + 2 = 32$$

Question 15

Which of the following is the correct Lewis Dot Structure for $$NH_4$$^+$$?

Accepted Answer

A nitrogen atom with four single bonds to hydrogen atoms, surrounded by brackets and a $$+$$ charge.

Lewis Dot Structures for Ions: Step-by-Step Guide and Practice

Study Guide - Practice Questions