Chemistry 101 Exam 3 Questions And
Correct Answers.
Type of process of the forming of the ionic compounds - Answer -reaction is exothermic
because of the lattice energy (it releases heat during formation)
-transfer of electron from metals to nonmetals is endothermic
ionic bond models - Answer -high heat to break apart lattice (high melting points) because
there are no free electrons
-nondirectional (as you move away from the center of the ion the forces are equally as strong in
all directions)
-ionic solids dissolve in water or melt, the cations and anions dissociate and free ions to allow
for electrical currents to flow through
ionic compound formulas - Answer -always contain positive and negative ions
-in a chemical formula, the sum of the charges of positive cations and negative anions are equal
-the formula of an ionic compound reflects the smallest whole number ratio of ions
common names - Answer -nicknames learned by familiarity
systematic names - Answer -determine from the chemical formula and vice versa
ionic compounds are made up of - Answer metals and nonmetals
electronegativity - Answer -ability of an atom to attract electrons to itself in a chemical bond
-increases across a period and decreases down a group
-larger the atom, the less ability it has to attract electrons to itself in a chemical bond
degree of polarity - Answer -depends upon the electronegativity difference between two
bonding atoms
-greater the difference, the more polar the bond
nonpolar (covalent) - Answer -two atoms with the same electronegativities form a covalent
bond and share electrons equally
ionic bond in terms of polarity - Answer -large electronegativity difference (such as normally
between a metal and nonmetal)
, polar covalent - Answer -intermediate electronegativity change
effect of electronegativity on the bond type - Answer Small change (0-.4) Covalent
Intermediate change (.4-2) Polar Covalent
Large change(2+) Ionic
dipole moment - Answer -occurs anytime there is separation of positive and negative charge
-magnitude of the moment=magnitude(q)*distance(r)
-units is in D (debye)
-quantify the polarity of a bond by the size of it's dipole moment
-smaller the magnitude of the charge separation and the smaller the distance between charges
the smaller the dipole movement
-more change in electronegativity means higher dipole movement
percent ionic character - Answer -ratio of a bond's actual dipole movement to the dipole
moment it would have if the electron were completely transferred from one atom to another
-(measure of dipole bond)/(dipole moment if electrons were completely transferred)*100
-bonds with greater than 50% ionic character are referred to as ionic bonds
total number of electrons for Lewis Structure - Answer (number of valence electrons in
element x)+(number of valence electrons in element y)+/-charge
resonance - Answer -used when two or more valid Lewis structures can be drawn for the same
compound
-when two or more Lewis structures have the same skeletal formula but different electron
arrangements
-when ****ing lewis structures can be flipped the opposite way why the ****ing hell the order
matters I couldn't tell you
-represent with a double headed arrow between the two ****ing options
-helps to account for the complexity of the actual molecules, since electrons are localized in
Lewis structures and in nature they are often delocalized
formal charge - Answer -an electron bookkeeping system that allows us to discriminate
between alternative Lewis structures
-fictitious charge assigned to each atom in a Lewis Structure that helps us to distinguish among
competing lewis structures
Correct Answers.
Type of process of the forming of the ionic compounds - Answer -reaction is exothermic
because of the lattice energy (it releases heat during formation)
-transfer of electron from metals to nonmetals is endothermic
ionic bond models - Answer -high heat to break apart lattice (high melting points) because
there are no free electrons
-nondirectional (as you move away from the center of the ion the forces are equally as strong in
all directions)
-ionic solids dissolve in water or melt, the cations and anions dissociate and free ions to allow
for electrical currents to flow through
ionic compound formulas - Answer -always contain positive and negative ions
-in a chemical formula, the sum of the charges of positive cations and negative anions are equal
-the formula of an ionic compound reflects the smallest whole number ratio of ions
common names - Answer -nicknames learned by familiarity
systematic names - Answer -determine from the chemical formula and vice versa
ionic compounds are made up of - Answer metals and nonmetals
electronegativity - Answer -ability of an atom to attract electrons to itself in a chemical bond
-increases across a period and decreases down a group
-larger the atom, the less ability it has to attract electrons to itself in a chemical bond
degree of polarity - Answer -depends upon the electronegativity difference between two
bonding atoms
-greater the difference, the more polar the bond
nonpolar (covalent) - Answer -two atoms with the same electronegativities form a covalent
bond and share electrons equally
ionic bond in terms of polarity - Answer -large electronegativity difference (such as normally
between a metal and nonmetal)
, polar covalent - Answer -intermediate electronegativity change
effect of electronegativity on the bond type - Answer Small change (0-.4) Covalent
Intermediate change (.4-2) Polar Covalent
Large change(2+) Ionic
dipole moment - Answer -occurs anytime there is separation of positive and negative charge
-magnitude of the moment=magnitude(q)*distance(r)
-units is in D (debye)
-quantify the polarity of a bond by the size of it's dipole moment
-smaller the magnitude of the charge separation and the smaller the distance between charges
the smaller the dipole movement
-more change in electronegativity means higher dipole movement
percent ionic character - Answer -ratio of a bond's actual dipole movement to the dipole
moment it would have if the electron were completely transferred from one atom to another
-(measure of dipole bond)/(dipole moment if electrons were completely transferred)*100
-bonds with greater than 50% ionic character are referred to as ionic bonds
total number of electrons for Lewis Structure - Answer (number of valence electrons in
element x)+(number of valence electrons in element y)+/-charge
resonance - Answer -used when two or more valid Lewis structures can be drawn for the same
compound
-when two or more Lewis structures have the same skeletal formula but different electron
arrangements
-when ****ing lewis structures can be flipped the opposite way why the ****ing hell the order
matters I couldn't tell you
-represent with a double headed arrow between the two ****ing options
-helps to account for the complexity of the actual molecules, since electrons are localized in
Lewis structures and in nature they are often delocalized
formal charge - Answer -an electron bookkeeping system that allows us to discriminate
between alternative Lewis structures
-fictitious charge assigned to each atom in a Lewis Structure that helps us to distinguish among
competing lewis structures
