Chapter 6 Review- Chemical Bonding

A chemical bond between atoms results from the attraction between the valence electrons and _______ of different atoms

nuclei

A covalent bond consists of

a shared electron pair

if two covalently bonded atoms are identical, the bond is identified as

nonpolar covalent

A covalent bond is which there is an unequal attraction for the shared electrons is

polar

Atoms with a strong attraction for the electrons they share with another atom exhibit

high electronegativity

Bonds that possess between 5% and 50% ionic character are considered to be

polar covalent

The greater the electronegativity difference between two Adams bonded together, the greater the bonds percentage of

ionic character

The electrons involved in the formation of a chemical bond are called

valence electrons

Chemical bond that results from the electrostatic attraction between positive and negative ions is called a

ionic bond

if electrons involved in bonding spend most of the time closer to one Adam rather than the other, the bond is

polar covalent

if a bond characters more than 50% ionic, than the bond is called a

ionic bond

A bond characters more than 50% ionic of the electronegativity difference between the two atoms is greater then

1.7

Nonpolar covalent compound example

H2

Polar covalent compound example

HCl

Ionic compound example

NaCl

Describe how I covalent bond holds two atoms together

A pair of electrons is attracted to both nuclei of the two atoms bonded together

What property of the two atoms is in a covalent bond determines whether or not the bond will be polar?

electronegativity

How can electronegativity be used to distinguish between an ionic bond in a covalent bond?

The difference between the electronegativity of the two atoms in a bond will determine whether the bond is ionic or covalent. If the difference in electronegativity is greater than 1.7, the bond is considered ionic.

Describe the electron distribution in a polar-covalent bond and it’s effects on the partial charges of the compound

The electrons density is greater around the more electronegative atom, giving that part of the compound a partial negative charge. The other part of the compound has an equal partial positive charge.

Use the concept of potential energy to describe how a covalent bond forms between two atoms

As the atoms involved in the formation of a covalent bond approach each other, the electron-proton attraction is stronger than the electron-electron and proton-proton repulsions. The atoms are drawn to each other and their potential energy decreases. Eventually, a distance reached at which the repulsion has the like charges equals the attraction of the opposite charges. At this point, potential energy is at a minimum and a stable molecular form.

Name two elements that form compounds that can be exceptions to the octet rule

Hydrogen, Boron, Beryllium, Phosphorous, Sulfur, and Xenon

Explain why resonance structures are used instead of Lewis structures to correctly model certain molecules

Resonance structures show that one Lewis structure cannot correctly represent the location of the electrons in a bond. Resident structures show delocalized electrons, while Lewis structures depict electrons in a definite location.

Identify the major assumption of the VS EPR theory, which is used to predict the shape of atoms.

Pairs of valence electrons repel one another

In water, two hydrogen atoms are bonded to one oxygen atom. Why isn’t water a linear molecule?

The electron pairs that are not involved in bonding also take up space, creating a tetrahedron of electron pairs and making water molecule angular or bent.

What orbitals combine together to form sp3 hybrid orbitals around a carbon atom?

The s orbital and all three p orbitals from the second electron energy level

What two factors determine whether or not a molecule is polar?

Electronegativity difference in molecular geometry or unshared electron pairs.

How are dipole – dipole attractions, London dispersion forces, and hydrogen bonding similar?

They’re all forces of attraction between molecules. In all cases there is an attraction between the slightly negatively charged portion of one molecule in the slightly positively charged portion of another molecule.

Is H-F nonpolar covalent, polar covalent, or ionic?

ionic

Is Na-Cl nonpolar covalent, polar covalent, or ionic?

ionic

Is H-O nonpolar covalent, polar covalent, or ionic?

polar covalent

Is H-H nonpolar covalent, polar covalent, or ionic?

nonpolar covalent

Is H-C nonpolar covalent, polar covalent, or ionic?

polar covalent

Is H-N nonpolar covalent, polar covalent, or ionic?

polar covalent

How is a hydrogen bond different from an ionic or covalent bond?

A hydrogen bond is a dipole – dipole attraction between a partially positive hydrogen atom and the unshared electron pair of a strongly electronegative atom such as O, N, or F. Unlike ionic or covalent bonds, in which electrons are given up or shared, the hydrogen bond is a weaker attraction. Hydrogen bonds are generally intermolecular, which ionic and covalent bonds occur between ions or atoms respectively.

H2S and H20 have similar structures and their central Adams belong to the same group. Yet H2S is a gas at room temperature and H2O is a liquid. Use bonding principles to explain why this is

Oxygen has higher electronegativity than sulfur, which creates a highly polar bond. Increase polarity in H2O bonds means a stronger intermolecular attraction making water a liquid at room temperature. Hydrogen bonding exists between water molecules, but not between hydrogen sulfide molecules.

In what way is a polar-covalent bond similar to an ionic bond?

There’s a difference between the electronegativity of the two atoms in both types of bonds that results in electrons being more closely associated with the more electronegative atom

Is H2S polar or nonpolar?

polar

Is COCl2 polar or nonpolar?

polar

Is PCl3 polar or nonpolar?

polar

Is CH2O polar or nonpolar?

polar