Chapter 4 Flashcards
What is the difference between a compound and a molecule?
A molecule is made of 2+ atoms, but
A compound is made of
2+ elements
Molecular formulas give the
exact number of
atoms of each element in a compound.
- Empirical formulas give the
lowest whole-number
ratio of atoms of each element in a compound.
A structural formulas is a
sketch or diagram of how
the atoms in the molecule are bonded to each other.
A molecular model is a more __________
A ball-and-stick molecular model
represents atoms as _____ and
chemical bonds as ______
− The balls are typically color-coded
to specific __________.
− How the atoms connect reflects a
____________.
6
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accurate
& complete way to specify a compound.
balls, sticks
elements
molecule’s shape
What happens to e- in an ionic bond?
e- transferred
What happens to e- in a covalent bond?
e- shared
What happens to e- in a metallic bond?
e- pooled
What does an ionic bond look like in the solid state?
Lattice of cations and anions
Lattice energy
The energy
required to
completely
separate a
mole of a solid
ionic compound
into its gaseous
ions.
Coulomb’s law
Distance increases, attraction decrases, charge is also higher but correlation, not causation
What state are ionic compounds in at room temp?
Solid
What teture are ionic compounds?
Brittle
What are ionic compounds melting/boiling temp?
High
What are covalent molecules also known as?
Molecular compound
How is bond length determined?
By which molecule has the lowest energy configuration
What is the melting/boiling point of molecular compounds?
Low
What state is molecular compounds found in at room temp?
All 3
What needs to be overcome to boil covalent substances?
Intermolecular attraction
What is the charge of zinc?
+2
What is the charge of silver?
+1
What is the charge of Aluminum (Need to know?)
+3
How do you name binary ionic compounds?
Metal + Nonmetal-ide
How do you name multivalent cations?
Metal (charge) + Nonmetal-ide
What are polyatomic ions? What do they have in common?
Molecules that contain multiple types of atoms, most are oxyanions
What are oxyanions?
Have O and one other element
More O atoms
per-, -Ate
Less O atoms
hypo, -Ite
How many O atoms do 2nd row -ate ions have?
3
How many O atoms do 3rd row -ate ions have?
4
How do you predict charges of 2nd row ions?
Relative to Oxygen
How do you predict charges of 3rd row ions?
Relative to Argon
How do you name molecular compounds?
Prefix- name of 1st element + Prefix-base name-ide. Put left one first.
Do you put mono for 1st element of molecular compounds?
No
What are the 2 different types of acids? How do you separate them?
Binary (2 elements) or Oxy (Contain oxygen)
How do you name binary acids?
Hydro + Base name of nonmetal + -ic acid
How do you name oxyacids if it ends in -ate?
Change -ate to -ic and add acid
How do you name oxyacids if they end in -ite?
Change -ite to -ous and add acid
What are organic compounds?
Hydrocarbons
Who discovered
that most main group elements gain, lose,
or share electrons to achieve 8 valence
electrons (2 s & 6 p e− s)? What is this called?
G.N. Lewis, the octet rule
What e- are involved in chemical bonding? Where are they?
Valence electrons, outer-shell
What are inner e- aka?
Core e-
Electrons shared by atoms are called
bonding pairs
− Electrons belonging to 1
particular atom are called
lone pairs
What is a a polar covalent bond?
Bond that doesn’t share e- equally
Electro-
negativity is
the ability of
atoms in a
molecule
to
attract e−s to
themselves.
Who discovered the concept of electronegativity?
Linus
Pauling
What is a dipole?
Molecule with positively and negatively charged ends
What is the dipole moment?
measure of the bond polarity (how big difference in e-negativity is)
Nonpolar covalent –∆EN
∆EN is 0 to 0.4.
Polar covalent –
∆EN
is 0.5 to 1.9.
Ionic – ∆EN
is
2.0 or greater.
Then formal charge of an atom is the charge it
would have if all of the bonding electrons were
shared equally between the bonded atoms.
What is the formula for formal charge?
Total VE-nonbonding e- - (bonding/2)
How do you find the best lewis structure?
Fewest charges, - charge on most e-negative atom
What scientist proposed that the electron in a hydrogen atom can only have certain energies (i.e., the electron is quantized)?
Bohr
What are resonance structures?
Alternate forms of a molecule that differ in e- placement
What happens to e- in double and single bonds?
They’re delocalized
What are the exceptions to the octet rule?
Ions with odd # of e (rare and unstable, called radicals)-, less than an octet, or more than 8 VE.
What do you prioritize when being forced to choose between filling octet of outer atoms or making double bonds?
Filling octet (slide 79)
What atoms can have more than 8 e-?
Atoms in D orbital
When should you expand an octet? (81)
When the central atom in on the
3rd row or below and expanding its octet
eliminates some formal charges
What are FCs values normally?
0
How many bonds does Nitrogen make?
3
How many bonds does Oxygen make?
2
How many bonds do halogens make?
1
