Chemistry Chapter 8 Flashcards
When sharing of electrons occurs, the attachment between atoms that results is called a…
Covalent bond
When such an attachment is formed, bond dissociation energy is released, and the process is..
exhotermic
When two or more atoms bond by means of electron sharing, the resulting particle is called a
molecule
If the electrons shared are centered between the two atoms, the attachment is called a
sigma bond
If the sharing involves the overlap of parallel orbitals, the attachment is called a
pi bond
How many electrons are shared in a double covalent bond?
four
Bond length is the distance between
the nuclei of two attached atoms
Which of the following relationships relating to bond length is generally correct?
the shorter the bond, the stronger the bond
Binary molecular compounds are generally composed of a metal and a nonmetal.
false
The second element in the formula of a binary compound is named using the
suffix -ite.
false
The prefix tetra- indicates three atoms.
false
The prefix hexa- indicates six atoms.
true
In naming the first element in a formula, the prefix mono- is not used.
true
For binary acids, the hydrogen part of the compound is named using the prefix
hydro-.
true
An oxyacid contains only two elements.
false
If the name of the anion of an oxyacid ends in -ate, the acid name contains the
suffix -ous.
false
CO
carbon monoxide
CO2
carbon dioxide
H2CO3
carbonic acid
NH3
ammonia
N2O4
Dinitrogen tetroxide
HNO2
Nitrous acid
HNO3
nitric acid
HBr
hyrdobromic acid
HBrO3
bromic acid
A structural formula shows the arrangement of the atoms in a molecule.
true
The central atom in a molecule is the one with the highest electron affinity.
false
In molecules, hydrogen is always a terminal atom.
true
The number of bonding pairs in a molecule is equal to the number of electrons.
true
To find the total number of electrons available for bonding in a positive ion, you
should add the ion charge to the total number of valence electrons of the atoms
present.
false
The electrons in a coordinate covalent bond are donated by both the bonded
atoms.
false
Resonance occurs when more than one valid Lewis structure can be written for a
molecule.
true
Nitrate is an example of an ion that forms resonance structures.
true
The carbon dioxide molecule contains two double bonds.
true
All electrons in an atom are available for bonding.
false
In the sulfate ion (SO42−), 32 electrons are available for bonding.
true
When carbon and oxygen bond, the molecule contains ten pairs of bonding
electrons.
false
Odd number of valence electrons
NO
. Fewer than 8 electrons around an atom
SF6
More than 8 electrons around central atom
O3
More than one valid Lewis structure
BF3
The VSEPR model is used mainly to
determine molecular shape
The bond angle is the angle between
two terminal atoms and the central atom.
The VSEPR model is based on the idea that
shared and unshared electron pairs repel each other as much as possible.
The shape of a molecule whose central atom has four pairs of bonding electrons is
tetrahedral
The shape of a molecule that has two covalent single bonds and no lone pairs on the central atom is6
linear
The shape of a molecule that has three single covalent bonds and one lone pair on the central atom is
trigonal pyramidal.
The formation of new orbitals from a combination or rearrangement of valence electrons is called
hybridization
The orbitals that are produced in this way are ________________________ to one another
identical
An example of an element that commonly undergoes such formation is
methane
When this atom combines its three p orbitals and its one s orbital, the orbitals that result are called ____________________ orbitals.
sp3
An example of a molecule that has this type of orbital is
carbon
What is the meaning of the term electronegativity?
electronegativity is the relative ability of an element’s atom to attract electrons in a chemical bond.
Which element has the highest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the highest overall electronegativities?
Fluorine (F) w/ 3.98. In the nonmetal familiy (group 17) it has the highest overall electronegatives.
Which element has the lowest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the lowest overall electronegativities?
Francium (Fr) w/ 0.7. In the metal family (group 1) it has the lowest overall electronegatives.
What general trend in electronegativity do you note going down a group? Across a period?
Going down a group, its numerical value decreases. Across a group, it decreases
How are the electronegativity values used to determine the type of bond that exists
between two atoms?
you subtract the values.
Ionic compounds are usually soluble in polar substances.
true
In a covalent molecular compound, the attraction between molecules
tends to be strong.
false
Unequal sharing of electrons between two bonded atoms always indicates
a polar covalent bond.
When electronegativities of two bonded atoms differ greatly, the bond is
ionic
What is the electronegativity difference that usually is the dividing line between covalent and ionic bonds?
1.7
Where is the symbol “sygma” placed next to?
the less electronegative atom in a polar covalent bond
A nonpolar covalent bond is one in which
electrons are shared equally
Molecules containing only polar covalent bonds
may or may not be polar.
What factor other than electronegativity determines whether a molecule as a whole is polar or not?
its geometry
Which of the following correctly describes the compound water, H2O?
polar overall, with nonpolar covalent bonds
Which of the following correctly describes the compound carbon tetrachloride, CCl4?
nonpolar overall, with polar covalent bonds
A molecule of ammonia, NH3, is
polar because there is an electronegativity difference and the molecule is trigonal pyramidal
