Question 1

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their highest energy level.

Question 2

What is the maximum number of electrons that can be found in the third energy level ($n=3$) of an atom?

Accepted Answer

$18$

Question 3

Which formula is used to calculate the maximum number of electrons in an energy level?

Accepted Answer

$2n^2$

Question 4

A sodium atom ($Na$) loses one electron to form a sodium ion. What is the charge and name of this ion?

Accepted Answer

Positive, sodium cation

Question 5

Which of the following ions is isoelectronic with neon ($Ne$)?

Accepted Answer

$Na^+$

Question 6

What is the correct chemical formula for the ionic compound formed between calcium ions ($Ca^{2+}$) and chloride ions ($Cl^-$)?

Accepted Answer

$CaCl_2$

Question 7

Which of the following statements about ionic compounds is TRUE?

Accepted Answer

Ionic compounds are formed by the transfer of electrons from metals to nonmetals.

Question 8

What is the name of the compound $FeO$?

Accepted Answer

Iron (II) oxide

Question 9

Which of the following ions is a polyatomic ion?

Accepted Answer

$SO_4^{2-}$

Question 10

If an atom of bromine ($Br$) gains one electron, what is the resulting ion and its charge?

Accepted Answer

$Br^-$, anion

Question 11

Which of the following is the correct formula for aluminum phosphate?

Accepted Answer

$Al_2(PO_4)_3$

Question 12

A magnesium atom ($Mg$) has 12 electrons. How many electrons are in its second energy level ($n=2$)?

Accepted Answer

$8$

Question 13

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a full valence shell of eight electrons (except helium).

Question 14

What is the correct name for the compound $CuCl_2$?

Accepted Answer

Copper (II) chloride

Question 15

Which of the following ions has a charge of $-2$?

Accepted Answer

$SO_4^{2-}$

Question 16

What is the correct formula for barium sulfate?

Accepted Answer

$BaSO_4$

Question 17

Which of the following is the correct formula for sodium carbonate?

Accepted Answer

$Na_2CO_3$

Question 18

If a potassium atom ($K$) loses one electron, what is the resulting ion and its charge?

Accepted Answer

$K^+$, cation

Question 19

Which of the following is the correct name for $Ca_3(PO_4)_2$?

Accepted Answer

Calcium phosphate

Question 20

Which of the following ions is formed when oxygen gains two electrons?

Accepted Answer

$O^{2-}$

Chapter 3: Octets of Electrons – Electron Arrangements and the Octet Rule

Study Guide - Practice Questions