Chem Ch. 6 Lewis Structure Construction Notes

What is the first step in drawing a Lewis structure for a molecule?

Count the total number of valence electrons in the molecule.

How do you account for charges (ions) when counting valence electrons?

Add one electron for each negative charge of anions, and subtract one electron for each positive charge of cations.

What should be considered when identifying the central atom in a Lewis structure?

The central atom is usually the least electronegative atom; exceptions are hydrogen and halogens, which are rarely central.

What represents a single bond in a Lewis structure?

A single line (dash) drawn between two atoms.

What must be done to complete the octet around atoms bonded to the central atom?

Place dots representing electrons around each atom as per teacher instructions.

What action should be taken if the central atom does not have a filled octet?

Consider making multiple bonds (double or triple bonds).

How should the Lewis structure of an ion be represented?

The entire structure should be placed in brackets with the charge written as a superscript on the upper right outside of the brackets.

What is the relationship between electron domains and the shape of a molecule?

The shape of a molecule or ion depends on the number of electron domains around the central atom.

What counts as an electron domain around the central atom?

Each nonbonding electron pair, single bond, double bond, and triple bond counts as an electron domain.

What is the significance of determining electron domain geometry?

It is important to be able to understand the underlying domain structure of a compound, which can be organized to have the lowest possible repulsions.

Which table is referenced to determine electron domain geometries?

The table entitled 'Electron Domain Geometries as a Function of the Number of Electron Domains'.

How do you determine molecular geometry after drawing the Lewis Structure?

By arranging the bonded atoms based on the electron domain geometry.

What is the first step in determining hybridization around the central atom?

Draw the Lewis structure for the molecule or ion.

How is electron domain geometry determined?

Using the VSEPR model.

What is the purpose of hybrid orbitals?

To accommodate the number of bonding electron pairs around the central atom.

What is the electron domain geometry for 2 electron domains?

Linear.

What is the hybridization for a molecule with 3 bonding domains and 0 nonbonding domains?

sp2.

What is the molecular geometry for 4 bonding domains and 0 nonbonding domains?

Tetrahedral.

What bond angle is associated with a trigonal planar molecular geometry?

120 degrees.

What is the molecular geometry for a central atom with 3 bonding and 1 nonbonding domain?

Trigonal pyramidal.

What defines electronegativity?

The tendency for an element to attract electrons towards itself in a bond.

What does polarity refer to in molecular terms?

Unequal distribution of electrons, causing an uneven charge distribution.

What happens to the molecular geometry when a lone pair is present?

It can alter the angles and shape compared to a molecule with all bonding domains.

In VSEPR theory, what is the effect of repulsion on molecular geometry?

Repulsions among electron domains lead to an arrangement that minimizes these repulsions.

How is hybridization represented in Lewis structures?

By indicating the number of hybrid orbitals required for bonding.