In the formation of an ionic bond between a metal and a nonmetal, what happens to the valence electrons?

Introduction / Context:
Ionic bonding is a fundamental concept in chemistry that explains how many salts and simple inorganic compounds form. It involves interactions between metals and nonmetals and the behavior of their valence electrons. This question focuses on what happens to valence electrons during the formation of an ionic bond and helps distinguish ionic bonding from covalent bonding, where electrons are shared rather than transferred.

Given Data / Assumptions:

• We consider a typical ionic bond between a metal atom and a nonmetal atom.
• The question asks about the fate of valence electrons, not core electrons.
• Options mention collisions, sharing, and transfer of electrons.

Concept / Approach:
In ionic bonding, metal atoms tend to lose one or more valence electrons to achieve a stable noble gas configuration, forming positively charged cations. Nonmetal atoms gain valence electrons to complete their valence shell and form negatively charged anions. The electrostatic attraction between these oppositely charged ions constitutes the ionic bond. Therefore, the key idea is the transfer, not sharing or simple collision, of valence electrons from the metal to the nonmetal.

Step-by-Step Solution:
Step 1: Recall that metals generally have low ionization energies and can lose valence electrons easily. Step 2: Recall that nonmetals have high electronegativities and tend to gain electrons to fill their valence shells. Step 3: When an ionic compound forms, such as NaCl, the sodium atom transfers one valence electron to the chlorine atom. Step 4: This transfer produces Na plus and Cl minus ions, which attract each other through electrostatic forces. Step 5: Compare this description with the options and select the one that mentions electrons being transferred and ions being formed.

Verification / Alternative check:
You can verify this by examining electron configurations. Sodium in the ground state has one valence electron in its outer shell, and chlorine needs one electron to complete its valence shell. After sodium transfers its electron to chlorine, sodium achieves a stable configuration similar to neon, and chlorine achieves a configuration similar to argon. The result is a stable ionic pair. This pattern is repeated in many ionic compounds, confirming that transfer of valence electrons and formation of ions is the defining feature of ionic bonding.

Why Other Options Are Wrong:
Option A suggests that electrons only collide and produce heat without actually transferring, which does not describe bond formation accurately. Option B talks about equal sharing of valence electrons, which is characteristic of covalent bonds, not ionic bonds. Option C combines collision and sharing, which again does not match the definition of ionic bonding. Only option D correctly states that valence electrons are transferred from one atom to another, leading to oppositely charged ions that attract each other.

Common Pitfalls:
Students sometimes confuse ionic and covalent bonds because both involve valence electrons and can produce stable structures. Another pitfall is to think of electrons as colliding rather than being transferred in a controlled way driven by differences in ionization energy and electron affinity. To avoid these mistakes, remember that ionic bonding always involves transfer of electrons and formation of ions, while covalent bonding involves sharing of electron pairs between atoms.

Final Answer:
In an ionic bond, valence electrons are transferred from one atom to another, forming oppositely charged ions that attract each other.