Module 3

Question 1

Lewis symbols show…

Answer 1

valence electrons on atoms and ions

Question 2

chemical bonding is

Answer 2

the attractive force between atoms in a compound

Question 3

chemical can be classified as

Answer 3

covalent, polar covent, non polar covalent, and ionic

Question 4

electronegativity is

Answer 4

a measure of the ability of an atom to attract electrons in a chemical bond

Question 5

the difference in electronegativity is used in classifying what?

Answer 5

the type of chemical bond, i.e. 0.5 and less is non polar covalent; 0.5 to 2.0 is polar covalent; and difference of 2.0 or larger is ionic

Question 6

monatomic ion

Answer 6

ions consisting of a single atom

Question 7

polyatomic ions

Answer 7

are composed of two or more atoms bonded together; although bonds to other ions with ionic bonds, they are themselves held together by covalent bonds

Question 8

In VSEPR theory, the main force that determines the geometry of a molecule is:

Answer 8

repulsion of the electron pairs in the molecule

Question 9

Ammonia is soluble in water because both ammonia and water molecules are __________. Oil and water don’t mix because oil is __________ and water is __________.

Answer 9

polar; nonpolar; polar

Question 10

Which of the following rules is not true when drawing Lewis dot structures for covalent molecules?

Answer 10

use the most electronegative atom as the central atom,

Question 11

A soluble ionic compound may __________ in water to form positive and negative ions, while a soluble covalent compound may __________ but will be a/an __________.

Answer 11

dissociate; dissolve; nonelectrolyte

Question 12

When no one single Lewis structure can adequately explain the electron distribution in a molecule, we conceptualize the ‘true’ structure as being a combination of all possible Lewis structures and call it a/an __________.

Answer 12

resonance hybrid

Question 13

Bonds in which electrons are shared unequally (i.e., the electrons spend more time around one atom than around the other) are called:

Answer 13

polar covalent

Question 14

Which of the following are the correct formulas for these ionic compounds: calcium chloride, sodium fluoride, potassium sulfide?

Answer 14

CaCl2; NaF; K2S

Question 15

Put these diatomic molecules in order from the most stable to the most reactive: O2, H2, N2.

Answer 15

nitrogen, oxygen, hydrogen; The most stable diatomic molecule is nitrogen, because it has a triple bond. The next in reactivity is oxygen, with a double bond. The most reactive molecule is hydrogen, with a single bond.

Question 16

What are the three basic molecular shapes that have the following bond angles between their component atoms? 180°, 120°, and 109.5°.

Answer 16

linear, trigonal planar, tetrahedral

Question 17

Which compound in each of the following pairs of compounds would you expect to have the higher boiling point? nitrogen vs. ammonia; water vs. potassium chloride; ethanol vs. hexane

Answer 17

ammonia; potassium chloride; ethanol, - The forces between ions in ionic compounds are very strong, so the melting and boiling points of these compounds are very high. The forces are quite a bit weaker for polar covalent molecules, and weakest of all for nonpolar covalent molecules, which have the lowest melting points and boiling points. Nitrogen is nonpolar, ammonia is polar; water is polar, potassium chloride is ionic; hexane is nonpolar, ethanol is polar.

Question 18

solubility is

Answer 18

the maximum amount of solute that dissolves in a given amount of solvent at a specific temperature

Question 19

Bonds in which electrons are shared unequally (i.e., the electrons spend more time around one atom than around the other) are called:

Answer 19

polar covalent

Question 20

__________ is a measure of an atom’s ability to attract electrons to itself within a chemical bond. Atoms with the highest values of this quantity are located in the __________ of the periodic table, while those with the lowest values are located in the __________ of the table.

Answer 20

electronegativity; top right area; bottom left area

Question 21

What are the correct names for these covalent compounds? N2O3, N2O4, N2O, and NO2

Answer 21

dinitrogen trioxide; dinitrogen tetroxide; dinitrogen oxide; nitrogen dioxide