Chemistry: Bonding, Molecular Shapes, and VSEPR Theory

What is a chemical bond?

A mutual attraction between the nuclei and the valence electrons of different atoms.

Why are atoms more stable when bonded together?

Bonding decreases potential energy, creating more stable arrangements of matter.

What is Ionic Bonding?

Chemical bonding that results from the electrical attraction between cations and anions.

What is Covalent Bonding?

Bonding that results from the sharing of electrons between two atoms.

Is a bond ever purely ionic or purely covalent?

No, it depends on the shared electrons being 'owned' equally by the two bonded atoms.

How can the ionic or covalent character of a bond be estimated?

By calculating the difference in the elements' electronegativities.

What is the ionic character of bonds between elements with an electronegativity of 1.7 or less?

50% or less, classified as covalent.

What type of bond do two atoms of the same element form?

A completely covalent bond.

What is a Nonpolar Covalent Bond?

A bond in which the bonding electrons are shared equally by the bonded atoms.

What is a Polar Covalent Bond?

A covalent bond in which the bonded atoms have unequal attraction for the shared electrons.

What is a molecule?

A neutral group of atoms that are held together.

Give an example of a molecule that exists as two or more of the same kind of atom.

Oxygen.

What is a molecular compound?

A chemical compound whose simplest units are molecules.

What does a chemical formula indicate?

The relative numbers of atoms of each kind in a chemical compound using atomic symbols.

What is a diatomic molecule?

A molecule that contains only two atoms.

Which elements exist as diatomic molecules?

Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine.

What is bond length?

The distance between the nuclei of two bonded atoms.

What is Bond Energy?

The energy required to break a bond between two atoms.

What does the Octet Rule state?

Atoms tend to form bonds to achieve a full outer shell of eight electrons.

What are the exceptions to the Octet Rule?

Hydrogen forms bonds with only two electrons; Boron tends to form bonds with six electrons.

What does VSEPR stand for?

Valence Shell Electron Pair Repulsion.

What is the purpose of VSEPR theory?

To predict the positions of electrons and the geometry of molecules.

What is the first step to determine the molecular shape?

Draw the Lewis Electron Dot Diagram for the molecule.

What is the most stable arrangement of regions with high electron density?

Linear, trigonal planar, tetrahedral, trigonal bipyramidal, or octahedral.

What is a trigonal pyramidal shape?

A molecular shape with three bonded atoms and one lone pair.

What is the shape of a molecule with four regions of high electron density?

Tetrahedral.

What is the shape of a molecule with two bonded atoms and one lone pair?

Bent.