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# 3.3.0.0: Bond Types (Problems)

PROBLEM $$\PageIndex{1}$$

Does a cation gain protons to form a positive charge or does it lose electrons?

Answer

The protons in the nucleus do not change during normal chemical reactions. Only the outer electrons move. Positive charges form when electrons are lost.

PROBLEM $$\PageIndex{2}$$

Iron(III) sulfate [Fe2(SO4)3] is composed of Fe3+ and $$\ce{SO4^2-}$$ ions. Explain why a sample of iron(III) sulfate is uncharged.

Answer

Two cations with a +3 charge give a total of +6 charge, while three anions of -2 charge give a total of -6 charge. +6-6=0, so when these ions bond, the charges will cancel, leaving the resulting compound uncharged.

PROBLEM $$\PageIndex{3}$$

Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: P, I, Mg, Cl, In, Cs, O, Pb, Co?

Answer

P, I, Cl, and O would form anions because they are nonmetals. Mg, In, Cs, Pb, and Co would form cations because they are metals.

PROBLEM $$\PageIndex{4}$$

Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: Br, Ca, Na, N, F, Al, Sn, S, Cd?

Answer

Anions: Br, N, F, S,

Cations: Ca, Na, Al, Sn (because it's a metal), Cd (because it is a metal)

PROBLEM $$\PageIndex{5}$$

Predict the charge on the monatomic ions formed from the following atoms in binary ionic compounds:

1. P
2. Mg
3. Al
4. O
5. Cl
6. Cs
Answer a

P3–

Answer b

Mg2+

Answer c

Al3+

Answer d

O2–

Answer e

Cl

Answer f

Cs+

PROBLEM $$\PageIndex{6}$$

Predict the charge on the monatomic ions formed from the following atoms in binary ionic compounds:

a. I
b. Sr
c. K
d. N
e. S
f. In

Answer a

I-

Answer b

Sr2+

Answer c

K+

Answer d

N3-

Answer e

S2-

Answer f

In3+

PROBLEM $$\PageIndex{7}$$

Write the noble gas electron configuration for each of the following ions:

a. As3–
b. I
c. Be2+
d. Cd2+
e. O2–
f. Ga3+
g. Li+
h. N3–
i. Sn2+
j. Co2+
k. Fe2+
l. As3+

Answer a

[Ar]4s23d104p6

Answer b

[Kr]4d105s25p6

Answer c

1s2

Answer d

[Kr]4d10

Answer e

[He]2s22p6

Answer f

[Ar]3d10

Answer g

1s2

Answer h

[He]2s22p6

Answer i

[Kr]4d105s2

Answer j

[Ar]3d7

Answer k

[Ar]3d6

Answer l

[Ar]3d104s2

PROBLEM $$\PageIndex{8}$$

Write out the full electron configuration for each of the following atoms and for the monatomic ion found in binary ionic compounds containing the element:

1. Al
2. Br
3. Sr
4. Li
5. As
6. S
Answer a

Al: 1s22s22p63s23p1

Al3+: 1s22s22p6

Answer b

Br: 1s22s22p63s23p63d104s24p5

Br-: 1s22s22p63s23p63d104s24p6

Answer c

Sr: 1s22s22p63s23p63d104s24p65s2

Sr2+: 1s22s22p63s23p63d104s24p6

Answer d

Li: 1s22s1

Li+: 1s2

Answer e

As: 1s22s22p63s23p63d104s24p3

As3-: 1s22s22p63s23p63d104s24p6

Answer f

S: 1s22s22p63s23p4

S2-: 1s22s22p63s23p6

PROBLEM $$\PageIndex{9}$$

What information can you use to predict whether a bond between two atoms is covalent or ionic?

Answer

The position of the two atoms on the periodic table: two nonmetals form a covalent bond, while a metal and a nonmetal form an ionic bond.

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