What is the main distinction between ionic and covalent bonding?
Electrons aren't equally shared in an ionic bond. The electronegativity difference is closer to zero in a covalent bond.
How is electronegativity used in determining the ionic or covalent character of the bonding between two elements?
Differences in electronegativity are calculated. If the difference is small, the bond is covalent. If the difference is large, the bond is ionic.
What type type of bonding would be expected between the following atoms?
a. Li and F
b. Cu and S
c. I and Br
b. Polar covalent
c. Nonpolar covalent or polar covalent
List the following pairs of atoms in order of increasing ionic character of the bonding between them.
a. Li and F
b. Cu and S
c. I and Br
I and Br, Cu and S, Li and F
Compare the following two pairs of atoms: Cu and Cl; I and Cl.
a. Which pair would have a bond with a greater percent ionic character?
b. In which pair would Cl have the greater negative charge?
a. Cu and Cl
b. Cu and Cl
The isolated K atom is larger than the isolated Br atom.
a. What type of bond is expected between K and Br?
b. Which ion in the compound KBr is larger?
b. Br- is the larger ion.
State the octet rule.
Atoms generally prefer to have a set of 8 electrons in their outermost energy level.
How many pairs of electrons are shared in the following types of covalent bonds?
a. a single bond
b. a double bond
c. a triple bond
a. 1 pair
b. 2 pair
c. 3 pair
Compare the molecules H2NNH2 and HNNH. Which molecule has the stronger N-N bond?
HNNH because it has a double bond between the nitrogen atoms.
Give two examples of an ionic compound.
NaCl and MgCl2 are two possible compounds. These are not the only two ionic compounds that could be used as answers.
Use electron-dot notation to demonstrate the formation of ionic compounds involving the following:
a. Li and Cl
b. Ca and I
See teacher edition
Distinguish between ionic and molecular compounds in terms of the basic units that each is composed of.
The basic unit of a molecular compound is a molecule. Molecules are not strongly connected to other molecules. The basic unit of an ionic compound is a formula unit. Formula units are strongly connected to nearby formula units.
Compound B has lower melting and boiling points than compound A. At the same temperature, compound B vaporizes faster than compound A. If one of these compouns is ionic and the other is molecular, which would you expect to be molecular? Explain your reasoning.
Compound B is probably molecular and A is probably ionic because ionic compound are typically harder to melt and boil.
The melting point for the compounds Li2S, Rb2S, and K2S are 900°C, 530°C, and 840°C, respectively. List these three compounds in order of increasing lattice energy.
Rb2S, K2S, and Li2S
Describe the electron-sea model of metallic bonding.
Metallic nuclei are positively charged and are surrounded by a sea of negatively-charged electrons. The nuclei and electrons are attracted to each other and form a bond. The electrons move freely and do not stay near their original metal atoms.
What is the relationship between metallic bond strength and enthalpy of vaporization?
Higher enthalpies correspond with stronger bonds.
Explain why most metals are malleable and ductile, but ionic crystals are not.
Atoms in ionic crystals must be arranged in a particular structure to remain together. If you shift them, they will no longer remain connected. Metals don't need to maintain a particular structure. As long as another metal atom is nearby, there will be a bond.
Explain why metals are good electrical conductors.
Electricity is the name given to the energy that comes from the movement of electrons. Electrons move freely within metals since they aren't firmly attached to a particular metal atom.
Draw the Lewis structure and predict the molecular geometry of SO2.
bent or angular, see teacher edition for Lewis structure.
Draw the Lewis structure and predict the molecular geometry of CI4.
tetrahedral, see teacher edition for Lewis structure.
Draw the Lewis structure and predict the molecular geometry of BCl3.
trigonal-planar, see teacher edition for Lewis structure.
What factors affect the geometry of a molecule?
The number of bonds and lone pairs surrounding the central atom will affect the geometry.
Explain what is meant by sp^3 hybridization
An s orbital has combined with a p orbital. Also, four electrons will be in the new sp^3 orbital.
What type of intermolecular force contributes to the high boiling point of water? Explain.
Hydrogen bonding. It is responsible for connecting one molecule to another. These bonds will have to be broken in order to separate H2O's molecules during vaporization.
What experimental property directly correlates with the strenghth of the intermolecular forces? Briefly explain your answer.
Boiling point. If it is difficult to boil a substance, it is probably because the molecules are being held together by intermolecular forces. Stronger forces will require more effort to overcome.