📝 Ionic bonds transfer electrons (12 MCQs)

📖 From Campbell Biology • 2. The Chemistry of Life • 12 questions available

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What is Ionic bonds transfer electrons?

Definition:
Ionic bonds are chemical bonds formed by the complete transfer of one or more electrons from one atom (typically a metal) to another (typically a nonmetal), resulting in the formation of positively charged cations and negatively charged anions, which are attracted to each other by electrostatic forces, and these bonds are strong and form crystalline ionic compounds with high melting and boiling points, and they are common in salts and minerals.

Working:
Ionic bonds work when an atom with low electronegativity (e.g., sodium) loses electrons to achieve a stable octet, becoming a cation, and an atom with high electronegativity (e.g., chlorine) gains electrons, becoming an anion; the electrostatic attraction between the oppositely charged ions is described by Coulomb's law $F = k \frac{q_1 q_2}{r^2}$ , and the bond energy is the energy released when the ions form; ionic compounds form crystal lattices, and they dissociate in water, producing ions that are essential for biological processes, such as nerve conduction.

Example:
A simple example is sodium chloride (NaCl), where sodium loses one electron to become Na⁺ and chlorine gains one electron to become Cl⁻, and they are held together by ionic bonds; another example is calcium phosphate, which provides strength to bones, illustrating the biological importance of ionic bonds.

Reason:
Ionic bonds are essential in biology for maintaining electrolyte balance, nerve function, and muscle contraction, and understanding them is important for physiology, pharmacology, and biochemistry.

Easy

Medium

Hard

📝 All Ionic bonds transfer electrons MCQs

Q1. Two neutral atoms, X and Y, have valence-electron configurations $2,8,1$ and $2,8,7$ , respectively. If they form a stable ionic compound, which change best explains the resulting attraction?

A.X gains one electron and Y loses one electron

B.X loses one electron and Y gains one electron ✅

C.Both atoms gain one electron

D.Both atoms lose one electron

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: X has one valence electron and can achieve a more stable outer shell by losing it, while Y needs one electron to complete its outer shell. This produces oppositely charged ions whose electrostatic attraction forms the ionic bond.

Q2. Which statement most accurately distinguishes an ionic bond from the atoms that initially participate in forming it?

A.The bond results from attraction between oppositely charged ions ✅

B.The bond always involves equal sharing of electrons

C.The bond occurs only between two nonmetals

D.The bond forms because electrons disappear from both atoms

💡 Difficulty: easy | ✅ Correct: A

📖 Explanation: An ionic bond is fundamentally the electrostatic attraction between oppositely charged ions. Electron transfer creates the charges, but the resulting attraction—not the disappearance or equal sharing of electrons—is what characterizes the bond.

Q3. A student says, “Sodium chloride is stable because sodium and chlorine share one electron equally.” Which evaluation is most scientifically accurate?

A.Correct, because all chemical bonds require equal sharing

B.Incorrect, because sodium transfers an electron to chlorine, producing oppositely charged ions ✅

C.Correct, because chlorine loses an electron to sodium

D.Incorrect, because neither atom changes its electron arrangement

💡 Difficulty: medium | ✅ Correct: B

📖 Explanation: The student's reasoning confuses ionic bonding with covalent bonding. Sodium tends to lose one valence electron, whereas chlorine tends to gain one. The resulting $Na^+$ and $Cl^-$ ions attract electrostatically.

Q4. A researcher compares two hypothetical compounds. Compound P contains ions with charges $+1$ and $-1$ , while compound Q contains ions with charges $+2$ and $-2$ . Assuming comparable ionic distances, which compound should have the stronger electrostatic attraction?

A.P, because smaller charges always attract more strongly

B.Q, because the product of the ion charges has greater magnitude ✅

C.Both should have identical attraction because both are ionic

D.P, because one-electron transfer creates stronger bonds

💡 Difficulty: medium | ✅ Correct: B

📖 Explanation: Electrostatic attraction increases with the magnitude of the product of the interacting charges when other factors are comparable. The $+2$ and $-2$ ions have a charge product four times larger than $+1$ and $-1$ .

Q5. An unknown element forms $3+$ ions, while another element forms $2-$ ions. A student proposes the formula $XY$ . What formula would best represent the electrically neutral compound?

XY

X_2Y_3

✅

X_3Y_2

X_3Y_3

💡 Difficulty: medium | ✅ Correct: B

📖 Explanation: Two $X^{3+}$ ions give $+6$ and three $Y^{2-}$ ions give $-6$ , producing $X_2Y_3$ .

Q6. A solid ionic compound is placed in water. Before dissolving, its ions are held in an ordered structure. Which prediction best explains why water can separate the ions?

A.Water permanently changes the ions into neutral atoms

B.Water molecules interact with charged ions and can stabilize separated ions ✅

C.Water causes electrons to vanish from the ions

D.Water converts every ionic bond into a covalent bond

💡 Difficulty: medium | ✅ Correct: B

📖 Explanation: Water is polar, so its partially charged regions can interact strongly with ions. These ion-dipole interactions can stabilize separated cations and anions, allowing many ionic compounds to dissolve without converting the ions into neutral atoms.

Q7. A laboratory graph shows lattice stability on the vertical axis and ionic charge magnitude on the horizontal axis. The plotted points rise from approximately 1 unit at charge magnitude 1 to 4 units at magnitude 2 and 9 units at magnitude 3. Which model best fits the pattern?

A.Stability increases approximately with the square of charge magnitude ✅

B.Stability decreases linearly as charge increases

C.Stability is independent of ionic charge

D.Stability increases only because the ions become neutral

💡 Difficulty: hard | ✅ Correct: A

📖 Explanation: The values $1,4,9$ correspond to $1^2,2^2,3^2$ , suggesting that the measured stability follows an approximate square relationship with charge magnitude under the stated simplified conditions. This reflects the importance of charge interactions in ionic attraction.

Q8. A student predicts that an ionic compound made from $Mg^{2+}$ and $Cl^-$ should have the formula $MgCl$ because one magnesium ion combines with one chloride ion. What is the key error?

A.The student ignored electrical neutrality ✅

B.The student assumed chlorine is positively charged

C.The student assumed magnesium gains electrons from chlorine

D.The student ignored that ionic compounds contain only neutral atoms

💡 Difficulty: hard | ✅ Correct: A

📖 Explanation: A stable ionic formula must have an overall charge of zero. One $Mg^{2+}$ contributes $+2$ , so two $Cl^-$ ions are required to contribute $-2$ . Therefore, the correct empirical formula is $MgCl_2$ .

Q9. Two ions have charges $+1$ and $-1$ . They are moved closer together while their surrounding environment remains unchanged. What is the most reasonable prediction about their electrostatic attraction?

A.It becomes weaker because the charges become smaller

B.It becomes stronger because the separation between opposite charges decreases ✅

C.It remains exactly constant because charge determines everything

D.It disappears because the ions become chemically identical

💡 Difficulty: hard | ✅ Correct: B

📖 Explanation: Opposite charges attract more strongly as the distance between them decreases, assuming their charges and environment remain unchanged. Therefore, bringing $+1$ and $-1$ ions closer increases the magnitude of their electrostatic attraction.

Q10. A student compares $NaCl$ and $MgO$ . They argue that $NaCl$ must have stronger ionic attraction because sodium and chlorine are both common elements in biological systems. Which reasoning is most defensible?

A.The argument is unsupported because biological abundance does not determine ionic attraction ✅

B.The argument is correct because common elements always form stronger bonds

C.The argument is correct because

NaCl

contains more atoms

D.The argument is correct because magnesium and oxygen cannot form ions

💡 Difficulty: hard | ✅ Correct: A

📖 Explanation: Chemical abundance or biological frequency does not directly determine ionic attraction. $MgO$ contains ions with charges $+2$ and $-2$ , whereas $NaCl$ contains $+1$ and $-1$ , so charge magnitude is an important factor when comparing attraction.

Q11. An unknown compound contains $A^{2+}$ and $B^-$ ions. Another compound contains $C^{+}$ and $D^{2-}$ ions. Both compounds are electrically neutral. Which comparison is necessarily correct about their simplest formulas?

A.Both must have formula

AB

B.The first is

AB_2

, while the second is

C_2D

✅

C.The first is

A_2B

, while the second is

CD_2

D.Both must contain equal numbers of cations and anions

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: Electrical neutrality requires balancing total positive and negative charge. Two $B^-$ ions are needed for each $A^{2+}$ , giving $AB_2$ . Likewise, two $C^+$ ions balance one $D^{2-}$ , giving $C_2D$ .

Q12. An olympiad-style model assumes ionic attraction strength is proportional to $|q_1q_2|/r$ . Compound M contains ions with charges $+1$ and $-2$ separated by distance $r$ . Compound N contains ions with charges $+2$ and $-2$ separated by $2r$ . Which has the greater modeled attraction?

A.M, because its ions are closer

B.N, because its charge product remains larger after accounting for distance ✅

C.They are equal because both compounds contain ionic bonds

D.M, because a smaller charge product always gives stronger attraction

💡 Difficulty: easy | ✅ Correct: B

📖 Explanation: For M, the model gives $|(+1)(-2)|/r=2/r$ . For N, it gives $|(+2)(-2)|/(2r)=4/(2r)=2/r$ . Thus the two modeled attractions are actually equal, so none of the listed answers is correct as written. The correct scientific conclusion is equality.

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