IB Chemistry Standard Level (SL) Practice Exam

The correct term for the electron dot structure that shows all valence electrons in a molecule is the Lewis dot structure. This model is named after Gilbert N. Lewis, who developed it to represent the arrangement of valence electrons around atoms in a molecule. In a Lewis dot structure, dots are used to depict valence electrons, emphasizing how these electrons can be shared or transferred between atoms to form bonds.

This method is particularly useful for visualizing covalent bonding, as it clearly displays pairs of electrons that form bonds and lone pairs that do not participate in bonding. The Lewis dot structure is foundational in understanding molecular geometry, polarity, and reactivity.

The other terms provided relate to different concepts in chemistry. The octet structure refers to a principle where atoms tend to form bonds in such a way that they achieve a full outer shell of electrons, typically eight. The valence shell model refers to a broader theory regarding the distribution of electrons in the outermost shell, while the hybridization model describes the mixing of atomic orbitals to form new hybrid orbitals for bonding. Each of these concepts has its own significance in understanding chemical bonding and molecular structure but do not specifically refer to the illustrative representation of valence electrons that the Lewis dot structure provides.