Ch 8: Covalent Bonding Flashcards
What is a bond that holds non-metal atoms together with other non-metal atoms?
Covalent bond
Which compounds have relatively lower melting and boiling points than ionic compounds?
Molecular compounds
Covalent compounds are made of a ______ ____ of electrons, of only ___-______.
shared pair
non-metals
_______ _____ hold covalent compounds together.
Covalent bonds
A _________ _______ shows how many atoms of each element a molecule contains.
molecular formula
In covalent bonds, when does electron sharing usually occur?
When atoms attain the electron configurations of noble gases.
Atoms ____, ____, or _____ electrons until stable. Need _.
gain
lose
share
8
Metals lose _________ electrons.
outermost
___-______ gain ____ to make 8.
Non-metals
more
An ________ ___ _________ such as H:H represents the shared pair of electrons of the ________ bond by two ____.
electron dot diagram
covalent
dots
What is the purpose of dot diagrams?
To understand the bonding in a compound and to use valance electrons as dots.
What number step is this (for making dot diagrams)?
“Find the sum of the valence electrons.”
1
What number step is this (for making dot diagrams)?
“Arrange the atoms with bonds between them (atoms that need more electrons are usually in the center). Connect the atoms with a dash.”
2
How many electrons are represented by each bond in an electron dot diagram?
2 electrons
What number step is this (for making dot diagrams)?
“Distribute remaining electrons to satisfy the Octet rule (except with exceptions).”
3
If there are not enough electrons to go around in an electron dot diagram, what do you do?
Try double or triple bonds.
Atoms form ______ or ______ covalent bonds if they can attain a noble gas structure by sharing ___ or _____ pairs of electrons.
double or triple
two or three
Where does the shared electron pair come from in a coordinate covalent bond?
It comes from one of the bonding atoms.
What does a large bond dissociation energy correspond to?
A strong covalent bond.
The actual bonding of oxygen atoms in ozone is a ______, or mixture, of the extremes represented by the _________ forms.
hybrid
resonance
The nitrate ion, benzene, and the acetate ion are all examples of what?
Resonance
If the double bond could have alternate positions or work in multiple places, what is to be suspected?
Resonance
The _____ rule cannot be satisfied in molecules whose total numbers of _______ electrons is an ___ number.
There are also molecules in which an atom has _____, or ____, than a complete octet of valence electrons.
octet valence odd fewer more
What are some exceptions to the octet rule?
(Stable with less) Hydrogen, Helium, Lithium, Beryllium, Boron, Transition metals.
(Stable with more) Phosphorus, Sulfur, Chlorine.
If there are an odd number of electrons when drawing an electron dot diagram, what do you do with the extra electron?
Put the extra electron on top of the bond, between the two electrons.
Just as an atomic orbital belongs to a particular atom, a molecular orbital belongs to a ________ as a whole.
molecule
According to VSEPR theory, the _________ between electron pairs causes molecular shapes to adjust so that the valence-electron pairs stay as ___ _____ as possible.
Repulsion
Far apart
What provides information about molecular bonding and molecular shape?
Orbital hybridization
The more electronegative atom attracts electrons more ________ and gains a slightly ________ charge.
The less electronegative atom has a slightly ________ charge.
Strongly
Negative
Positive
When polar molecules are placed between oppositely charged plates, they tend to become oriented with respect to the ________ and ________ ______.
Positive and negative plates
Melting a network solid would require breaking what throughout the solid.
Covalent bonds
