Why do elements form compounds?

• A. To increase their atomic number
• B. To achieve a more stable electron configuration, often by attaining a full valence shell
• C. To decrease their atomic mass
• D. To become radioactive

Answer: (B)

Verified step by step guidance

1. Understand that elements form compounds primarily to achieve greater stability in their electron arrangements.
2. Recall that atoms are most stable when they have a full valence shell, which usually means having eight electrons in their outermost shell (the octet rule), except for some elements like hydrogen and helium.
3. Recognize that atoms can gain, lose, or share electrons through chemical bonds (ionic or covalent) to complete their valence shells.
4. Note that increasing atomic number or decreasing atomic mass are not reasons for compound formation; these are nuclear properties, not related to chemical bonding.
5. Conclude that the driving force behind compound formation is the attainment of a more stable electron configuration, which lowers the overall energy of the system.