day 1 naming compounds writing formulas. swbat l write and name binary and tertinary ionic compounds...
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Systematic Naming There are too many compounds to
remember the names of them all. Compound is made of two or more
elements. Put together atoms. Name should tell us how many and
what type of atoms.
Periodic Table More than a list of elements. Put in columns because of similar
properties. Each column is called a group.
5 Types of Chemical Compounds
•Binary ionic - metal ion – nonmetal ion
•Ternary ionic - at least one ion is a polyatomic ion
•Binary molecular - two nonmetals
•Binary acid - H – nonmetal
•Ternary acid - H – Polyatomic ion
Atoms and ions Atoms are electrically neutral. Same number of protons and electrons. Ions are atoms, or groups of atoms,
with a charge. Different numbers of protons and
electrons. Only electrons can move. Gain or lose electrons.
Anion A negative ion. Has gained electrons. Non metals can gain electrons. Charge is written as a superscript on
the right.
F1- Has gained one electron
O2- Has gained two electrons
Cations Positive ions. Formed by losing electrons. More protons than electrons. Metals form cations.
K1+ Has lost one electron
Ca2+ Has lost two electrons
2+
1+
3+ 3- 2- 1-
Charge in groups 1A, 2A and 3A is the group number
in 5A, 6A and 7A is the group number - 8
Naming Binary Ionic Compounds Binary Compounds - 2 elements. Ionic - a cation and an anion. The name is just the names of the ions. Cation first anion second Easy with Group A elements. NaCl = Na+ Cl- = sodium chloride
MgBr2 = Mg2+ Br- = magnesium bromide
Na2S
Naming Binary Ionic Compounds The problem comes with the transition
metals. Cation name includes the charge. The compound must be neutral. same number of + and – charges. Use the negative charge to find the
charge on the positive ion.
Naming Binary Ionic Compounds Write the name of CuO Need the charge of Cu O is 2- copper must be 2+ Copper(II) oxide Name CoCl3 Cl is 1- and there are three of them = 3- Co must be 3+ Cobalt(III) chloride
Polyatomic ions Groups of atoms that stay together
and have a charge. Covalently bonded You must memorize these.
A Few Polyatomic Rules: PA ions which contain Oxygen contain
endings of -ite ( the least amount of Oxygen )and –ate ( the greater amount).
For ex.
Sulfite SO32- and Sulfate SO4
2-
Nitrite NO21- and Nitrate NO3
1-
Polyatomic Rules cont. Hydrogen is often indicated by an ions
name when present. For ex.: Hydrogen sulfate HSO4
1-
The prefixes mono- and di- are sometimes used.
For ex.: Dihydrogen phosphate H2PO41-
The prefix thio- means, replace an Oxygen with a Sulfur.
1- ions Acetate C2H3O2
1-
Nitrate NO31-
Nitrite NO21-
Hydroxide OH1-
Permanganate MnO41-
Cyanide CN1-
2- ions Sulfate SO4
2-
Sulfite SO32-
Carbonate CO32-
Chromate CrO42-
Dichromate Cr2O72-
Silicate SiO32-
Adding Hydrogen to Polyatomics Hydrogen ions are 1+ Attach to other polyatomic ions-
changes charge by one Sulfate SO4
2-
Hydrogen sulfate HSO41-
Phosphate PO43-
Hydrogen phosphate HPO42-
Dihydrogen phosphate H2PO41-
Ternary Ionic Compounds Will have polyatomic ions At least three elements (3 capital letters) Still just name the ions
NaNO3
CaSO4
CuSO3
Writing Formulas The charges have to add up to zero. Get charges on pieces. Cations from name or periodic table. Anions from periodic table or polyatomic. Balance the charges by adding subscripts. Put polyatomics in parenthesis if there is
more than one of them
Writing Formulas Write the formula for calcium chloride. Calcium is Ca2+
Chloride is Cl1- Ca2+ Cl1- would have a 1+ charge. Need another Cl1- Ca2+ Cl2
1-
Write the formulas for these Lithium sulfide tin (II) oxide tin (IV) oxide Copper (II) sulfate Iron (III) phosphide gallium nitrate Iron (III) sulfide ammonium sulfide
Yes
Charge from name
Charge from table
No
Formula and
charge from
memory
Charge from table
Yes No
M+X Nm-Y
MYNmX
Ionic
Roman Numeral?
Polyatomic?
Things to look for If cations have (), the number is their
charge. Not how many. If anions end in -ide they are probably off
the periodic table (Monoatomic) If anion ends in -ate or -ite it is polyatomic The positive piece always gets written first Hydrogen- it depends on where it’s at
– If it is second, it’s a nonmetal -hydride
Molecular compounds made of just nonmetals smallest piece is a molecule can’t be held together because of
opposite charges. can’t use charges to figure out how
many of each atom
Easier Ionic compounds use charges to
determine how many of each.
– Have to figure out charges.
– Have to figure out numbers. Molecular compounds name tells you
the number of atoms. Uses prefixes to tell you the number
Naming
Exception - we don’t write mono- if there is only one of the first element.
No ao oo double vowels when writing name, io, oi, and ai are okay.
Prefix name Prefix name -ide
To write the name write two words