What is a covalent bond
Chemical bond that results in the sharing of valence electrons
a covalent bond forms between two ___
nonmetals
How does a covalent bond form?
2 nonmetals- attractive and repulsive force- attractive force is greater- they bond and share electrons
List the elements that exist as diatomic molecules. Why do they exist as diatomic molecules?
Hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
What is a single covalent bond?
one pair of electrons is shared
What two things does the strength of a covalent bond depend on?
bond length and bond dissociation energy
What is bond length?
distance between two bonding nuclei
How are bond length and shared pairs of electrons related?
as the number of shared pairs increases the bond length decreases
How are bond length and strength of the bond related?
shorter the bond length the stronger the bond. single < double < triple
What is bond dissociation energy?
amount of energy needed to break a covalent bond.
How are bond length and dissociation energy related?
2 atoms bonded closer more energy needed to separate
What are resonance structures?
condition that occurs when more than one valid lewis structure can be written for a molecule
What does VSEPR stand for?
Valence Shell Electron Pair Repulsion Model
What is the VSEPR theory?
minimizes the repulsion of shared and unshared pairs of electrons around the central atom
What is a bond angle?
the angle formed by any two terminal atoms and a central atom
Draw the linear shape and describe.
2 shared pairs, 0 lone pairs, nonpolar
Draw a bent shape and describe.
2 shared pairs, 2 lone pairs, polar
Draw a tetrahedral shape and describe.
4 shared pairs, 0 lone pairs, nonpolar
Draw a trigonal planar shape and describe
3 shared pairs, 0 lone pairs, polar
Draw a trigonal pyramidal shape and describe.
3 shared pairs, 1 lone pair, polar
When are two atoms likely to form a double bond?
...
When are two atoms likely to form a triple bond?
...
What is electronegativity?
Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.
What is a nonpolar covalent bond?
equal sharing of electrons. 2 nonmetals same electronegativity
What is a polar covalent bond?
unequal sharing of electrons, difference in electronegativity
Where do the electrons spend more time in a polar covalent bond?
around one atom. the atom is momentarliy negative. the other atom is momentarily positive, creates a dipole- 2 poles
What did the paddles represent in the molecule building kits?
lone pairs of electrons
Where are lone pairs located?
the central atom
How many electrons do two atoms in a double covalent bond share?
4
a structural formula shows the arrangement of the atoms in a molecule
true
in molecules, hydrogen is always a terminal atom
true
the number of bonding pairs in a molecule is equal to the number of electrons
false
to find the total number of electrons available for bonding in a positive ion, yo should add the ion charge to the total number of valence electrons of the atoms present
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
true
when carbon and oxygen bond, the molecule contains ten pairs of bonding elements
false
the vespr model is used mainly to
determine molecular shape
the bond angle is the angle between
two terminal atoms and the central atom
the vespr 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 is
linear
the shape of a molecule that has three single covalent bonds and one lone pair on the central atom
triagonal pyramidal