When two neutral atoms form a chemical bond to create a molecule, what actually happens at the level of electrons?

Introduction / Context:
Chemical bonding explains how atoms join together to form molecules and compounds. Whether the bond is ionic, covalent or metallic, it is always related to the behaviour of electrons, especially the outermost valence electrons. Understanding this helps explain why some elements form salts, others form molecules and how stable structures like water, sodium chloride and methane arise. This question asks what fundamentally happens when two atoms form a chemical bond.

Given Data / Assumptions:

• We are considering typical chemical bonds between atoms, not nuclear reactions.
• The atoms are neutral before bonding.
• Options mention fusion, electron sharing or transfer, proton transfer and attraction of like charges.
• We assume basic knowledge of ionic and covalent bonding models.

Concept / Approach:
In ionic bonding, one atom transfers one or more valence electrons to another, forming positive and negative ions that attract each other. In covalent bonding, atoms share pairs of electrons to fill their outer shells. In both cases, it is the electrons that move or are shared, not protons. Protons are located in the nucleus and do not normally move from one atom to another in ordinary chemical reactions. Fusion or changing the nucleus belongs to nuclear reactions, not chemical bonding. Like charges repel, not attract, so bonds cannot be formed by attraction of like charges.

Step-by-Step Solution:
Step 1: Recall that valence electrons in the outermost shell determine bonding behaviour.Step 2: In an ionic bond, such as in sodium chloride, a sodium atom loses an electron to a chlorine atom, forming Na+ and Cl−, which then attract each other.Step 3: In a covalent bond, such as in water or methane, atoms share electron pairs so that each achieves a stable configuration similar to a noble gas.Step 4: In both cases, electrons are either transferred or shared; protons remain in the nuclei and do not move between atoms.Step 5: Consider the options and choose the one that mentions sharing or transfer of electrons for stability.Step 6: Option b correctly states that atoms share electrons or transfer electrons to achieve more stable configurations.

Verification / Alternative check:
You can test this by thinking of simple Lewis dot diagrams. When you draw NaCl, you show one electron moving from Na to Cl. When you draw H2, O2 or H2O, you show pairs of dots representing shared electrons between atoms. There is never a diagram where protons are moved or shared, and no diagram shows atoms physically fusing into one larger atom during ordinary chemical bonding. These representations match the idea of electron transfer or sharing as the core of bonding.

Why Other Options Are Wrong:
Option a describes nuclear fusion, which changes the identity of elements and requires extremely high energies, not ordinary chemical bonding. Option c incorrectly mentions transfer or sharing of protons, which does not occur in typical chemical reactions. Option d speaks of like charges attracting, which contradicts basic electrostatics where like charges repel. Option e suggests atoms lose all their electrons and become bare nuclei, which does not happen under normal chemical conditions and would not lead to stable molecules.

Common Pitfalls:
Students sometimes confuse chemical bonding with nuclear reactions because both are studied in similar chapters. Another pitfall is to focus only on one type of bond, such as covalent, and forget that ionic bonds involve electron transfer, not sharing. To avoid confusion, always remember that chemical bonds involve valence electrons moving or being shared to allow atoms to achieve more stable electron configurations.

Final Answer:
When two atoms form a chemical bond, they share electrons or transfer electrons in order to reach more stable electron configurations.