Chemistry Chapter 12 Test Review

A bonds character is more than 50% ionic if the electronegativity difference between the two atoms is greater than

1.7

Describe the force that holds two ions together in an ionic bond.

A positively charged ion and a negatively charged ion are attracted and bonded.

A covalent bond consists of _____.

A shared electron pair.

Bond energy is related to bond length. Use the data in the tables below to arrange the bonds listed in order of increasing bond length, from shortest to longest. Bond Energy (kJ/mol) - C-C 346 - C=C 835 - C≡C 612

C-C 346, C=C 612, C=C 835. -

The notation for sodium chloride, NaCl, stands for one

Formula unit.

Bond energy is related to bond length. Use the data in the tables below to arrange the bonds listed in order of increasing bond length, from shortest to longest. Bond Energy (kJ/mol) - H-F 569 - H-I 299 - H-Cl 432 - H-Br 366

H-I 299, H-Br 366, H-Cl 432, H-F 569.

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

High electronegativity.

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

Hydrogen and sulfur.

Describe the electron distribution in a polar-covalent bond and its effect on the partial charges of the compound.

If the two atoms are attracting and one atom has a higher electronegativity to pull electrons away from the other atom, the atom pulling the electrons will become slightly more negative than the other atom in the bond.

A chemical bond that results from the electrostatic attraction between positive and negative ions is called a(n)

Ionic bonds.

If the bond's character is more than 50% ionic, then the bond is called a(n)

Ionic bonds.

What types of bonds are present in an ionic compound that contains a polyatomic ion?

Ionic bonds.

The greater the electronegativity difference between two atoms bonded together, the greater the bond's percentage of

Ionic character.

What type of energy best represents the strength of an ionic bond?

Lattice energy.

Compared with the neutral atoms involved in the formation of an ionic compound, the crystal lattice that results is

Lower in potential energy.

Arrange the ionic bonds in the table below in order of increasing strength from weakest to strongest. Bond Lattice Energy (kJ/mol) NaCl -787 CaO -3384 KCl -750 MgO -3760 LiCl -861

MgO -3760, CaO -3384, LiCl -861, NaCl -787, KCl -750.

In a crystal of an ionic compound, each cation is surrounded by a number of

Negative ions.

If two covalently bonded atoms are identical, the bond is identified as _____.

Nonpolar covalent.

Write the formula for an example of each of the following compounds: nonpolar covalent compound polar covalent compound ionic compound

Nonpolar covalent: Fe 1.8 - Mn 1.5 = .3 Polar covalent: S 2.5 - Ca 1.0 = 1.5 Ionic: F 4.0 - K .8 = 3.2

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

Nuclei.

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

Polar covalent.

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

Polar covalent.

A convalent bond in which there is an unequal attraction for the shared electrons is _____.

Polar.

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

The difference of the electronegativity of the both atoms determines whether the bond is covalent or ionic.

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

The electronegativity of the atoms.

Describe how a covalent bond holds two atoms together.

The pair of electrons shared by the atoms is attracted to both of the nuclei of the bonded atoms.

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

The resonance structure shows the last electrons in the bond while the Lewis structure only shows the exact location.

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

Valence electrons.

The forces of attraction between molecules in a molecular compound are generally

Weaker than the attractive forces among formula units in ionic bonding.

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

When atoms are repulsed from each other, they are unstable, but when they are attracted to a point where the distance of attraction and repulsion are equal ], they become stable and form covalent bonds.