Question

activity b: ionic compounds
get the gizmo ready: click reset. turn off show charge. select lithium (li) and oxygen (o).
question: how are ionic compounds formed?

1. observe: look at the purple lithium atom and the red oxygen atom. recall that most atoms are stable when their outermost ring has eight electrons. some atoms, such as lithium and beryllium, are stable when their outermost ring has two electrons.

a. how many electrons will the lithium atom give up to become stable? ____________
b. how many electrons does the oxygen atom need to become stable? ____________
c. can a stable compound be made from these two atoms? explain why or why not.

1. form bonds: click add metal to add another lithium atom, and then transfer electrons from the lithium to the oxygen. click check.

a. did you make a stable compound? ________
b. turn on show formula. what is the formula of this compound? ____________
c. turn on show charge. what is the charge of each ion? li __ li o __

1. practice: use the gizmo to create stable compounds from the combinations given below. after transferring electrons, arrange the atoms to demonstrate the attraction between positively charged ions and negatively charged ions. click check to check each compound.

for each compound, click the camera ( ) icon to take a snapshot. right - click the image, and click copy image. paste each image into a blank document to turn in with this worksheet. write the ionic charges (such as ca²⁺) and chemical formulas below.
ionic charges chemical formula
a. lithium and fluorine: li f ____________
b. beryllium and oxygen: be o ____________
c. magnesium and fluorine: mg f ____________
d. aluminum and chlorine: al cl ____________
e. beryllium and nitrogen: be n ____________

Explanation:

Step1: Analyze lithium electron - transfer

Lithium has 3 electrons with an electron - configuration of 2,1. To have a stable outer - shell (2 electrons in its case), it will give up 1 electron.

Step2: Analyze oxygen electron - requirement

Oxygen has 8 electrons with an electron - configuration of 2,6. It needs 2 more electrons to have a stable outer - shell of 8 electrons.

Step3: Determine compound stability

Two lithium atoms can each give 1 electron to an oxygen atom. So, a stable compound can be made because the lithium atoms will become stable with 2 electrons in their outer - shell and the oxygen atom will become stable with 8 electrons in its outer - shell.

Step4: Answer part 2A

Yes, a stable compound is made.

Step5: Answer part 2B

The formula of the compound formed by two lithium atoms and one oxygen atom is $Li_2O$.

Step6: Answer part 2C

Lithium ion ($Li^+$) has a charge of + 1. Since two lithium atoms are involved, both have a charge of + 1. The oxygen ion ($O^{2 - }$) has a charge of - 2.

Step7: Answer part 3A

Lithium loses 1 electron to become $Li^+$, and fluorine gains 1 electron to become $F^-$. The chemical formula is $LiF$.

Step8: Answer part 3B

Beryllium loses 2 electrons to become $Be^{2+}$, and oxygen gains 2 electrons to become $O^{2 - }$. The chemical formula is $BeO$.

Step9: Answer part 3C

Magnesium loses 2 electrons to become $Mg^{2+}$, and each fluorine atom gains 1 electron to become $F^-$. Two fluorine atoms are needed, and the chemical formula is $MgF_2$.

Step10: Answer part 3D

Aluminum loses 3 electrons to become $Al^{3+}$, and each chlorine atom gains 1 electron to become $Cl^-$. Three chlorine atoms are needed, and the chemical formula is $AlCl_3$.

Step11: Answer part 3E

Beryllium loses 2 electrons to become $Be^{2+}$, and nitrogen gains 3 electrons to become $N^{3 - }$. To balance the charges, 3 beryllium atoms and 2 nitrogen atoms are needed. The ionic charges are $Be^{2+}$ and $N^{3 - }$, and the chemical formula is $Be_3N_2$.

Answer:

1. A. 1

B. 2
C. Yes, because two lithium atoms can each give 1 electron to an oxygen atom, making the lithium atoms stable with 2 electrons in their outer - shell and the oxygen atom stable with 8 electrons in its outer - shell.

1. A. Yes

B. $Li_2O$
C. $Li^+$, $Li^+$, $O^{2 - }$

1. A. $Li^+$, $F^-$, $LiF$

B. $Be^{2+}$, $O^{2 - }$, $BeO$
C. $Mg^{2+}$, $F^-$, $MgF_2$
D. $Al^{3+}$, $Cl^-$, $AlCl_3$
E. $Be^{2+}$, $N^{3 - }$, $Be_3N_2$