chapter 3 naming Flashcards
what can pure substances be divided into?
Pure substances can be either elements or compounds
what are elements subdivided into?
• Elements are subdivided into:
!Atomic (eg. Ne)
!Molecular (eg. H2)
what are compounds subdivided into?
• Compounds are subdivided into:
!Molecular (CO2)
!Ionic (CaF2)
what is a compound?
A compound is a distinct substance that is composed
of atoms of two or more elements
The properties of a compound are different than those
of the elements that form the compound
what do chemical bonds result from?
• Chemical bonds result from attractive forces
between atoms
• Not all bonds are created equal
what is an ionic bond
Ionic - When electrons are fully transferred from
one atom to another
what is a covalent bond?
Covalent - When electrons are shared between
atoms
what do covalent bonds form between?
• When two atoms share the bonding electrons
• Typically form between two non-metals (H is
an exception)
Compounds formed from covalent bonds are
called molecular compounds
what do ionic bonds form from?
Generally occurs between a metal and a non
metal
• Ionic compounds are formed when positively
charged cations and negatively charged anions
are held together by ionic bonds
how to predict ionic and molecular compounds?
Ionic compounds: Most metals readily lose electrons to
form cations and non-metals accept electrons to form
anions
• Molecular compounds: Non-metals don’t want to give
up electrons readily, so they share
what are the three kinds of chemical formulas?
Empirical - relative number of atoms of each element in a
compound
Molecular - actual number of atoms of each element in a
molecule of a compound
Structural - uses lines to represent covalent bonds and
show how atoms are connected
how is the empirical formula found?
• From the given chemical formula you reduce the ratio of
atoms by the largest common denominator
• The empirical formula can be the same as the molecular
formula
what does the molecular formula give?
Always a whole number multiple of the empirical
formula
• Gives the actual stoichiometric ratio of elements in a
compound
• Molecular compounds are generally expressed by
their molecular formulas
what are ionic compounds expressed with?
Ionic compounds are expressed by their empirical
formula, which is the same as the molecular formula
what is the molecular formula of an ionic compound based on?
The molecular formula of an ionic compound is based on the formula unit The formula unit is the smallest electrically neutral combination of atoms Formula unit=molecular formula Na+ + Cl- ➔ NaCl
steps for the formula of an ionic compound
All ionic compounds are charge neutral NaCl, MgI2, Al2O3 1. Write the atomic symbols and predicted charges for each ion 2. Balance charges: crossover superscripts as the subscripts Al3+ O2- Al3+ O2- Al2O
what are multivalent cations?
Some metals are able to form more than one cation
• Determined by their electron configuration
Can determine which cation is present based on the
subscripts in the ionic formula
how do we name ionic compounds?
Need to recognize compound as ionic (metal & nonmetal)
• Cations with only one possible charge are given the
same name as the metal; Na+ sodium, Mg2+ magnesium
• Cations that can have multiple charges retain the name
followed by the charge number in roman numerals; Fe2+/
Fe3+ iron(II)/iron(III), Cu+/Cu2+ copper(I)/copper(II)
• Monoatomic anions consists of the base name with the
suffix -ide; Cl-
= chloride
what is the lattice structure of ionic compounds?
• Ionic compounds form between a metal and non-metal
• The metal transfers electron(s) to the non-metal
• Opposite charges attract, so more than one unit of the
compound can be attracted to each other
• These intermolecular attractive forces allow ionic
compounds to form an extended lattice structure
how do we write ionic compound formulas?
Molecular formula = empirical formula = formula unit
The formula unit is the smallest electrically neutral
combination of atoms.
After crossing over ion charges to subscripts you need
to check that the formula you are left with is the formula
unit.
what is a polyatomic ion?
Ions with more than one atom
• Name by the same conventions except with the
name of the polyatomic ion name
what is an oxyanion? naming suffix?
Oxyanions are named based on the number of oxygen
atoms - contain oxygen and at least one other element
When there are two oxyanions in the family:
1. The oxyanion with the least oxygens ends in the
suffix -ite
2. The oxyanion with the most oxygens ends in the
suffix -ate
oxyanions with more than 2 in family
Note that the charge remains the same
When there are more than two oxanions in the family:
1. The anion with the most O atoms has the prefix
per- and the suffix -ate
2. the anion with one fewer O atoms ends in the suffix
-ate
3. The anion with two fewer O atoms has the suffix -
ite
4. the anion with 3 fewer O atoms has the prefix
hypo- and the suffix -ite
trends in polyatomic oxyanions
- Group 17 (7A) elements form a series of 4 oxyanions
- Group 16 (6A) elements form two oxyanions
- Group 15 (5A) elements form two oxyanions
- Group 14 (4A) elements form one or two oxyanions
what determines the overall charge of the anion? exceptions?
• Overall charge of the anion is determined by the central atom (nonoxygen) • Two exceptions are C and N
look at chart for polyatomic oxyanions. can they include hydrogen?
- Some oxyanions can also include a hydrogen
* Add hydrogen in front of the name of the oxyanion
5 steps to write formula for ionic compounds containing a polyatomic ion
1. Write the symbol for the cation and its charge 2. Write the symbol for the anion and its charge 3. Balance charges: Charge (without sign) becomes subscript for other ion 4. Reduce subscripts to smallest whole number ratio 5. Check that the total charge of the cations cancels the total charge of the anions
what are hydrates?
Ionic compounds that contain a specific number of water molecules • The water molecules are indicated at the end of the name with prefix hydrate
prefixes for before hydrate
hemi 1/2 mono 1 di 2 tri 3 tetra 4 penta 5 hexa 6 hepta 7 octa 8 nona 9 deca 10
what are binary molecular compounds
• Unlike ionic compounds, looking at the
constituent elements does not allow you to
determine the molecular formula
• Contain two (or more) atoms of two nonmetals
• Generally, 1st element is the smallest group
number, if both are in the same group the larger
row number comes first
how do we name binary compounds?
prefix name of 1st element prefix base name of 2nd element + -ide
what are acids?
• Acids are molecular compounds that release H+
when dissolved in water
• Normally exist as either binary or oxyacids
what are binary acids? naming?
- Composed of hydrogen and non-metal
- Add hydro in front of base name of non-metal
- Add suffix -ic to the end of non-metal
- Add acid to the end of the name
4 steps for naming binary acids
1. Identify the anion Br = Br−, bromide because Group 7A 2. Name the anion with an –ic suffix Br− = bromide -> bromic 3. Add a hydro- prefix to the anion name hydrobromic 4. Add the word acid to the end hydrobromic acid
what are oxyacids? naming?
• Contain hydrogen and an oxyanion
• Name depends on the oxyanion only
• Suffix at the end of the oxyanion determines the suffix
for the oxyacid
• -ate means -ic; -ite means -ous
• Oxyacid must be charge neutral; balance the oxyanion
charge with hydrogen
how do we write formulas for acids?
• When name ends in acid, formulas starts with H
• Write formulas as if ionic, even though it is molecular
• Hydro prefix means it is binary acid, no prefix means it is
an oxyacid
• For oxyacid, if ending is –ic, polyatomic ion ends in –ate;
if ending is –ous, polyatomic ion ends in –ous
what are organic compounds?
• The main element that is the focus of organic
chemistry is carbon
• Organic compounds are mainly made of C and
H, sometimes with O, N, P, S, halogens, and
trace amounts of other elements
• The difference between organic chemistry and
inorganic chemistry is an organizational
one…not a fundamental one
what are the kinds of hydrocarbons?
Types of Hydrocarbons Alkane Only C-C single bonds Alkene Contain C-C double bonds Alkyne Contain C-C triple bonds
describe alcohols
-ol ending
R-OH
describe ethers
ether ending
R-O-R’
solvent
describe aldehydes
-al ending
o
double bond
R-C - H
fragrance/flavorsdescribe kentones
-one ending
o
double bond
R-C - R’
describe carboxylic acids
acid ending
0
double bond
R-C-OH
describe esters
-ate ending
o
double bond
R-C-OR’
describe amines
amine ending
RNH2
smell of rotten fish
