Bonds within...
Metals, Ionic and Covalent Compounds
Properties Related to Bonding I
Properties Related to Bonding II
IMFs
100
The type of bond holding two atoms together within a compound, (ionic or covalent) can be predicted by comparing ____ values for the two atoms.
What is electronegativity?
100
Compounds that are held together by covalent bonds can form separate _____ that can range in size from two to several thousand atoms.
What are molecules?
100
When struck, the realignment of the ions within the lattice results in like charges (two cations or two anions) lining up next to each other. When this happens, the forces of repulsion cause the lattice to split, making ionic compounds ___
What is brittle?
100
What types of bonds or forces have to be overcome to boil a ...
___ network covalent solid? ___ covalent compound? ___ ionic compound? ___ metal?
What is covalent?
What is intermolecular forces?
What is ionic?
What is metallic?
100
_____ bonding, a type of intermolecular force, exists when the slightly negative end of one polar molecule is bonded to the slightly positive end of another polar molecule.
What is dipole-dipole?
200
A bond between two atoms is considered to be primarily ___ if the EN difference between the two atoms is greater than 1.7.
What is ionic?
200
____ compounds form a crystal lattice of repeating cations and anions.
What is ionic?
200
For aluminum to melt, you must overcome the ___ bonding that holds this metal together as a solid.
What is metallic?
200
Of the following, ____ solids would conduct electricity.

covalent compound
ionic compound
metallic

Explain.
What is metal?

Current travels through the movement of ions or electrons, and only metallic solids have free-flowing electrons.
200
_____ bonding, a type of dipole-dipole bond, exists when the hydrogen on one polar molecule is attracted to an F, O, or N on another polar molecule. Why is this type of dipole-dipole bond so strong?
What is hydrogen?

This type of bond is so strong because the EN difference is so great between H and F, O, or N that the dipole is much larger. A larger dipole makes the H end of the polar molecule really slightly positive and the F, O or N end really slightly negative. Think of it like magnets, because these molecules are more polar, they are like stronger magnets, and they are held together more tightly.
300
If two nonmetal atoms bond, the bond will be primarily ___ in character.

Justify your answer.
What is covalent?

The EN of two nonmetals would be fairly similar, which means an EN difference of less than 1.7 (unlike the EN difference of a metal/nonmetal bond, which would be higher than 1.7 for an EN difference).
300
______________ BETWEEN one molecule and another are broken when a covalent solid dissolves in water.

Justify your answer.
What is intermolecular forces?

In a covalent solid like sugar, polar water pulls one sugar molecule away from another, causing the sugar to dissolve. The covalent bonds within the molecule aren't broken (the C doesn't break apart from the H or the O), the bonds BETWEEN the molecules, (LD, DD, and HB), are, leaving separate tiny little molecules of sugar floating around in the water when they dissolve.
300
When a/n ___ (ionic/covalent) compound dissolves in water, it doesn't conduct electricity.

Explain why.
What is covalent?

Ions must be present for current to be conducted, and no ions are present when covalent compounds dissolve.
300
If a nonpolar compound exists as a liquid, it is because ______ are present BETWEEN separate molecules holding them together as a liquid.

What are intermolecular forces?

300
London dispersion forces are present between ___ molecules.
What is ALL?
400
In a/n ____ bond, delocalized electrons flow through a lattice of cations. What properties can be explained by these delocalized electrons?
What is metallic?

A metal's conductivity, (both heat and electricity), malleability, and luster can be explained by delocalized electrons.
400
___ bonds and ___ bonds are so strong that they cannot be broken by the addition of heat from a Bunsen burner nor by polar water molecules pulling them apart in solution.

What evidence do you have from lab that these bonds are strong?
What is covalent and metallic?

We know these bonds are strong because SiO2 and Al didn't dissolve, nor did they melt when heated with the Bunsen burner. (This is unlike sugar, which did dissolve, but remember, sugar dissolving doesn't break the covalent bonds within the compound, it breaks the intermolecular forces BETWEEN the molecules.
400
The strength of London dispersion forces relates to the total number of ionizable electrons present. The more ionizable electrons present, the ____ the LD forces

Given this relationship, would you expect the LD forces between two carbon tetrafluorides or two carbon tetrachlorides, both of which are nonpolar molecules, to be greater? Justify your answer.
What is greater?

Because CF4 has 42 ionizable electrons, (therefore 84 ionizable electrons between two CF4 molecules) and CCl4 has 74 ionizable electrons, (therefore 148 ionizable electrons between two CCl4 molecules), the LD forces holding two CCl4 molecules together is stronger.
400
Covalent bonds are ____ (weaker/stronger) than ionic bonds.

Justify your logic.
What is stronger?

Table salt dissolves in water, which means that polar water molecules can pull the Na+ and Cl- ions apart (breaking the ionic bonds). When sugar dissolves in water, the covalent bonds holding the carbons, hydrogens and oxygens together aren't broken, just the intermolecular forces holding sugar molecules together are broken.
400
Two SF6 molecules would be held together with ________ bonds.

Justify your answer.
What is London dispersion?

SF6 is a nonpolar molecule, and nonpolar molecules are held together by LD forces.
500
_________ bonds hold nonmetal atoms (not ions) together in lattice.

What are two examples of substances that are held together by this type of bonding.
What is network covalent?

Diamond and sand (SiO2)
500
The covalent bonds holding atoms together within a molecule are ______ (weaker/stronger) than the intermolecular forces holding one molecule to another to form a covalent solid.

Justify your answer.
What is stronger?

When sugar dissolves in water, the intermolecular forces holding two molecules of C12H22O11 together break, the covalent bonds holding the carbons, hydrogens and oxygens together WITHIN the molecule of sugar don't.
500
Boiling points of covalent compounds are based on the amount of energy it takes to overcome the bonds holding the individual molecules together, the more energy it takes to break the intermolecular forces, the ___ the boiling point.

Both NH3 and CH4 have a simliar number of ionizable electrons, yet NH3 has a higher boiling point (-33 oC) than CH4, which has a boiling point of -164 oC. Explain why.

.
What is higher?

Because both compounds have a similar number of ionizable electrons, the fact that NH3 is polar and CH4 is nonpolar must be the explanation. The dipole-dipole bond (or hydrogen bond) between the two NH3 molecules takes more energy to overcome, so NH3 has a higher boiling point.
500
Heating metals to high temperatures causes the atoms within the metal to vibrate. This vibration interferes with the movement of the free-flowing electrons through the metal, therefore reducing the electrical conductivity of the metal.

Based on this, would you expect stainless steel, which is an alloy (mixture) of metals containing a small percent of interspersed carbon atoms, to be a better or worse conductor of electricity than pure metal?
What is worse?

A worse conductor because the interspersed nonmetal atoms would make it more difficult for the electric current to pass through the metal.
500
Two SF4 molecules would be held together with ______________ bonds.

Justify your answer.
What are London dispersion AND dipole-dipole?

SF4 is a polar molecule, and polar molecules are held together by LD forces and DD bonds.
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