Lewis Dot Structures and VSEPR Theory Flashcards

Comprehensive practice flashcards covering Lewis structures, VSEPR molecular shapes, bond angles, hybridization, octet exceptions, and molecular polarity from the lecture context.

Who created Lewis Dot Structures and in what year?

Gilbert Lewis created Lewis Dot Structures in $1916$.

What do dots and dashes represent in a Lewis dot structure?

One dot represents one valence electron, and one dash represents a covalent bond consisting of two electrons.

According to the HONC rule, how many covalent bonds do Hydrogen, Oxygen, Nitrogen, and Carbon typically form?

Hydrogen (and halogens) forms $1$ covalent bond, Oxygen (and sulfur) forms $2$, Nitrogen (and phosphorus) forms $3$, and Carbon (and silicon) forms $4$.

What are the specific exceptions to the octet rule mentioned for Boron, Phosphorus, Sulfur, and Xenon?

Boron is stable with $6$ valence electrons, Phosphorus with $10$ valence electrons, Sulfur with $12$ valence electrons, and Xenon with $16$ valence electrons.

What central atom requirement is used when drawing Lewis dot structures for compounds containing more than two total atoms?

The atom that wants the most bonds is placed as the central atom.

What is the core principle of Valence Shell Electron Pair Repulsion (VSEPR) theory?

Electron pairs around a central atom arrange themselves so they can be as far apart as possible from each other.

What are the bond angle, hybrid orbital, number of bonded atoms, and number of unshared electron pairs for a Tetrahedral molecule?

A Tetrahedral shape has a bond angle of $109.5^\bullet$, an $\text{sp}^3$ hybrid orbital, $4$ bonded atoms, and $0$ unshared pairs of electrons on the central atom.

What are the bond angle, hybrid orbital, and unshared electron pair count for a Trigonal Planar molecule?

A Trigonal Planar shape has a bond angle of $120^\bullet$, an $\text{sp}^2$ hybrid orbital, $3$ bonded atoms, and $0$ unshared pairs of electrons on the central atom.

What key structural details distinguish a Bent molecule from a Linear molecule?

A Linear molecule typically has a group $14$ central atom with $0$ unbonded electron pairs, whereas a Bent molecule typically has a group $16$ central atom with $2$ unbonded electron pairs.

What bond angles correspond to Linear, Trigonal Planar, Tetrahedral, Trigonal Pyramidal, and Bent shapes according to the VSEPR notes?

Linear is $180^\bullet$, Trigonal Planar is $120^\bullet$, Tetrahedral is $109.5^\bullet$, Trigonal Pyramidal is $107^\bullet$, and Bent is $104.5^\bullet$ (or $105^\bullet$).

How are ionic, polar covalent, and nonpolar covalent bonds defined based on the elements involved?

Ionic bonds occur between elements on opposite sides of the periodic table (metal + nonmetal); polar covalent bonds occur between two nonmetals on the right side with unequal sharing; nonpolar covalent bonds occur between two atoms of the same element on the right side with equal sharing.

How can symmetry be used to distinguish between a polar and a nonpolar molecule?

A polar molecule has asymmetric electron distribution with only $1$ line of symmetry, while a nonpolar molecule has symmetrical electron distribution with $2$ or more lines of symmetry.

Which molecular geometries are inherently polar and nonpolar for binary compounds?

Bent and Trigonal Pyramidal shapes are polar, while Linear, Trigonal Planar, and Tetrahedral shapes are nonpolar.

What are the molecular shape and electron geometry for a central atom with generic formula $\text{AX}_3\text{E}$?

The molecular shape is Trigonal Pyramid (or Pyramidal) and the electron geometry is Tetrahedral.

What are the molecular shape and electron geometry for a central atom with generic formula $\text{AX}_2\text{E}$?

The molecular shape is Bent and the electron geometry is Trigonal Planar.

What are the names and chemical formulas of the three simple two-carbon hydrocarbon molecules listed in the carbon-based molecules notes?

Ethane ($\text{C}_2\text{H}_6$), Ethene ($\text{C}_2\text{H}_4$), and Ethyne ($\text{C}_2\text{H}_2$).