Transcript Packet 7 Part I

Chemical Formulas-Ionic
Chapter 6 Sections 1-4
Classifying Elements-Metals
 Are located to the left side of the
staircase line on the periodic table
 Display the following properties





Malleability
Luster
Ductility
Conduct heat
Conduct electricity
 Tend to lose electrons to form positive
Classifying Elements-Nonmetals
 Are located to the right of the
staircase line on the periodic table
 Display the following properties




Soft and brittle
Have an odor
Do not Conduct heat or electricity
Many are gases at room temperature
 Tend to GAIN electrons and form
negative ions
Classifying Elements-Metalloids
 Are the elements directly touching the
staircase line of the periodic table.
 Exhibit both properties of metals and
nonmetals
 May form either positive or negative
ions
 Generally, the elements at the top of
the periodic table make positive ions
and those at the bottom form negative
ions
Periodic Table colored to show
metals, nonmetals, and
metalloids
http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/pertab.html
Ions
 An ion is an atom with a chargeeither positive or negative
 Positive ions are called CATIONS.
They have lost electrons.
 Negative ions are ANIONS. They have
gained electrons.
 A polyatomic ion has more than one
atom attached with the charge.
Oxidation Number
 The charge and the number that
represents the number of electrons
lost or gained.
23
11
Na
19
9
F
1
-1
This is a cation with 1 missing
electron.
This is an anion with 1
extra electron
Binary vs. Ternary
 The prefix “bi” means two. Binary
compounds have only TWO elements
in their formula.
 Ternary compounds have three
elements in their chemical formula.
Formula
 A Formula is a shorthand way to
represent a chemical compound
using symbols and numbers.
Name:
Calcium
Phosphate
Ca3(PO4)2
Calcium symbol
A Subscript: 3 Calcium ions
Phosphate ion
made up of 1
phosphorous and
4 oxygen atoms
2 Phosphate ions
In the Real World
 Follow the link to learn the formulas
for our gemstones.
 http://pubs.usgs.gov/gip/gemstones/
formulas.html
Formulas
 Easily written
 The sum of the positive charges and the
negative charges must add up to be zero!
 Subscripts will be used to multiply
charges if needed
 You will sometimes use parentheses with
polyatomic ions.
 The “criss-cross” method will help check
your work
Criss-Cross Method
Mg
2
P
Mg3P2
-3
Naming Ionic Compounds
 The positive ion name is the name of
its element
 The negative portion will have a
special ending
 Single atom ion will end in
 -ide
 Polyatomic ions end in either
 -ate
 -ite
 -ide
Roman Numerals/Stock System
 Many of the transition metals are
troublesome because they can have
more than one oxidation number
 Iron can be Fe+3 or Fe+2
 Copper might be Cu+1 or Cu+2
 We indicate which form of the metal
we used by a roman numeral:
 Iron(III) is Fe?
 Cu+2 is Copper(?)
Practice
 This unit absolutely requires that you
practice using the naming rules!
 That’s why there are several labs and
worksheets
 This item also appears on the TAKS
test, so I don’t want you to just learn
it for the test and forget the
information!