Why can a hydrogen atom form a covalent bond without fulfilling the octet rule?

• A. Because hydrogen can share up to eight electrons with other atoms.
• B. Because hydrogen has a full d subshell that makes the octet rule unnecessary.
• C. Because hydrogen loses all its electrons when forming covalent bonds.
• D. Because hydrogen only needs two electrons to achieve a stable electron configuration like helium.

Answer: (D)

Verified step by step guidance

1. Understand the octet rule: it states that atoms tend to form bonds to have eight electrons in their valence shell, achieving a noble gas configuration.
2. Recognize that hydrogen is an exception to the octet rule because it only has one electron and its first shell (1s orbital) can hold a maximum of two electrons.
3. Know that hydrogen achieves stability by sharing one electron with another atom, thus having two electrons in its valence shell, similar to the electron configuration of helium.
4. Realize that hydrogen cannot share up to eight electrons because it lacks p and d orbitals; its valence shell is limited to the 1s orbital.
5. Conclude that hydrogen forms covalent bonds by sharing electrons to complete its duet (two electrons), not an octet, which explains why the octet rule does not apply to hydrogen.