Chemistry Flashcards
Endothermic Reaction
A reaction that occurs when more energy is required during product bond formation than is released when the new bonds form in the product.
Exothermic Reaction
A reaction that occurs when more energy is released during product bond formation
Why do atoms bond?
Atoms bond in order to reach a full outer energy level and achieve a noble gas configuration.
What is a covalent bond and how is it formed?
A covalent bond is a chemical bond that results from sharing valence electrons.
What is a molecule and how is it formed?
A molecule is formed when two or more atoms bond covalently.
What is a diatomic molecule?
A diatomic molecule is a molecule composed of only two atoms.
What is a “Lewis structure”?
They are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.
Group 17 can form how many covalent bonds?
1 covalent bond.
Group 16 can form how many covalent bonds?
2 covalent bonds.
Group 15 can form how many covalent bonds?
3 covalent bonds.
Group 14 can form how many covalent bonds?
4 covalent bonds.
Single covalent bonds are also called
Sigma bonds. (σ)
What is a sigma bond and how does it occur?
A sigma bond is otherwise called a single covalent bond and occurs when the pair of shared electrons is in an area centered between the two atoms.
List the orbitals that can form sigma bonds in a covalent compound, such as in DNA molecules.
- s and s orbitals
- s and p orbitals
- p and p orbitals
What is a double bond and how does it form?
A double bond is a double covalent bond and forms when two pairs of electrons are shared between two atoms.
What is a triple bond and how does it form?
A triple bond is a triple covalent bond and forms when three pairs of electrons are shared between two atoms.
A multiple covalent bond consists of what two types of bonds?
1 sigma bond and 1 pi bond.
What is a pi bond and how does it occur?
A pi (π) bond is a shared electron pair that occupies the space above and below the line that represent where the two atoms are join together.
It occurs when parallel orbitals overlap and share electrons.
The strength of a covalent bond depends on what
The distance between the two bonded nuclei.
What is bond length?
It is the distance between the two bonded nuclei and their maximum attraction.
How are bond length and bond strength related
The shorter the bond length, the stronger the bond.
(The more covalent bonds, the stronger the attraction.)
What is bond-dissociation energy and what type of value is it?
Bond-dissociation energy is the amount of energy required to break a specific covalent bond, it is always a positive value.
What is a coordinate covalent bond and how does it form?
A coordinate covalent bond is a bond that is formed by one atom donating both both of the electrons to be shared with an atom or ions that needs two electrons to form a stable electron configuration.
What is Resonance?
Resonance is a condition that occurs when more than one valid Lewis structure can be written for an ion or molecule.
How do you name a Binary molecular compound?
First, the first element in the formula is written fully, (N for nitrogen). The second element is named using its root and adding the suffix -ide, (O root is ox + -ide = oxide). Finally add prefixes.
What prefix is used for 1 atom?
mono-
What prefix is used for 2 atoms?
di-
What prefix is used for 3 atoms?
tri-
What prefix is used for 4 atoms?
tetra-
What prefix is used for 5 atoms?
penta-
What prefix is used for 6 atoms?
hexa-
What prefix is used for 7 atoms?
hepta-
What prefix is used for 8 atoms?
octa-
What prefix is used for 9 atoms ?
nona-
What prefix is used for 10 atoms?
deca-
What are the two types of acids?
Binary acids and oxyacids
How do you name binary acids?
Start with hydro- , then take the root of the second element and add the suffix -ic. (hydrochloric acid.)
What is a binary acid?
A acid in which there are only two elements, hydrogen and a second nonmetallic element.
How do you name an oxyacid?
First, identify the oxyanion present, then take it’s root and add per- or hypo-, (only if it is part of the oxyanions name.) then, if the oxyanions name ends with -ate change it to -ic, and if -ite, then -ous.
What is an oxyacid?
An acid that contains both hydrogen and an oxyanion.
What do you change -ate to?
-ic
What do you change -ite to?
-ous
What is a structural formula?
A molecular model that uses letter symbols and bonds to show relative positions of atoms.
What are the exceptions to the octet rule?
- If there are an odd number of valence electrons.
- If there are any suboctets or coordinate covalent bonds.
- If there are any expanded octets.
What hybrid orbitals and bond angle(s) are given if the shape is linear?
sp
180 degrees.
What hybrid orbitals and bond angle(s) are given if the shape is trigonal planar?
sp^2
Trigonal planar
What hybrid orbitals and bond angle(s) are given if the shape is Tetrahedral?
sp^3
109.5 degrees.
What hybrid orbitals and bond angle(s) are given if the shape is Trigonal pyramidal?
sp^3
107.3 degrees.
What hybrid orbitals and bond angle(s) are given if the shape is Bent?
sp^3
104.5 degrees.
What hybrid orbitals and bond angle(s) are given if the shape is Trigonal bipyramidal?
sp^3d
90 degrees from vertically, and 120 degrees horizontally.
What hybrid orbitals and bond angle(s) are given if the shape is Octahedral?
sp^3d^2
90 degrees vertically and horizontally.
What bond character is present when the EN difference is greater than 1.7?
Mostly ionic.
What bond character is present when the EN difference is between 0.4 - 1.7?
Polar covalent.
What bond character is present when the EN difference is less than 0.4?
Mostly covalent.
What bond character is present when the EN difference is 0?
Nonpolar covalent.
What is electronegativity?
The relative ability of an atom to attract electrons for bonding.
What is a polar covalent bond?
Is a covalent bond in which the electron pairs between different atoms are not shared equally.
What are intermolecular forces also known as?
van der Waals forces.
Molecules that produce hydrogen in solutions are
acids.
Binary acids contain what two elements?
Hydrogen and one other element.
Oxyacids contain which 3 elements?
Hydrogen, oxygen and 1 other element.
