Which of the following correctly represents the Lewis dot structure for the neutral compound calcium phosphide (Ca3P2)?

• A. Each Ca atom loses two electrons to form Ca2+ ions, and each P atom gains three electrons to form P3− ions; the structure consists of three Ca2+ ions and two P3− ions.
• B. The structure consists of neutral Ca and P atoms with no transfer or sharing of electrons.
• C. Each Ca atom shares electrons with P atoms to form covalent bonds, resulting in a structure with shared electron pairs.
• D. Each Ca atom gains two electrons to form Ca2− ions, and each P atom loses three electrons to form P3+ ions.

Answer: (A)

Verified step by step guidance

1. Identify the type of bonding in calcium phosphide (Ca3P2). Since calcium is a metal and phosphorus is a nonmetal, the compound is ionic, meaning electrons are transferred rather than shared covalently.
2. Determine the common oxidation states: calcium typically forms Ca^{2+} ions by losing two electrons, and phosphorus typically forms P^{3-} ions by gaining three electrons to achieve a stable electron configuration.
3. Calculate the total charge balance: with three Ca atoms each losing 2 electrons, the total positive charge is +6; with two P atoms each gaining 3 electrons, the total negative charge is -6, resulting in a neutral compound overall.
4. Represent the Lewis structure by showing three Ca^{2+} ions (no dots around Ca since they lose electrons) and two P^{3-} ions with eight dots (representing the gained electrons) around each phosphorus atom to complete their octet.
5. Confirm that the structure reflects ionic bonding with electron transfer (not sharing), consistent with the formula Ca3P2, where the ratio of Ca^{2+} to P^{3-} ions balances the charges.