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Physical Science, Advanced
Instructional Objective:
1.identify the difference between ionic and
covalent compounds
2.Learn about the bonds
Ions
• An atom with a charge.
• It can be positive or negative in
charge.
• It can be obtain by loosing or gaining
electrons. (Protons never change)
Cations
•
•
•
•
•
•
Are always positive in charge.
Obtain by loosing electrons.
Always going to be a metal
Written using the symbol with a + sign
Ex. Na+ Proton – 11, electron -10
Roman numerals are used to show the
charge of certain metals.
• Ex: Fe 3+ is named as Iron III
Anions
• Are always negative in charge.
• Obtain by gaining electrons
• Always going to be a nonmetal
• Written using a symbol with a
negative sign.
• Ex: Cl – (Proton -17 ,electron -18)
What is an oxidation number?
• valence electron: electron in the
outermost energy level of an atom
• oxidation number: number of
electrons an atom gains, loses, or
shares when it forms a chemical
bond
What is a chemical
equation?
chemical equation:
*chemical formula that describe a
chemical reaction
coefficient:
• number that shows how many
molecules of a substance are in a
chemical reaction
• Used to balance an equation
Ionic Compound
•
•
•
•
Metal and a nonmetal combined.
Always a cation and anion
Net charge will be zero.
Named as metal first ,then the nonmetal
that ends with ide,ite,ate.
• Ex. Sodium Chloride (Name)
NaCl (Symbol)
• To write the symbol use the crisscross
method to cancel the charges.
• Ex:
Metals with multiple ions
• Many transition metals have more
than one oxidation number.
• It is always indicated with roman
Numeral number.
• Ex: Copper II
Copper I
Chromium II
Chromium III
Two types of ionic
compounds
• Binary ionic compound
• *Contain two elements
• *Contain a metal and a nonmetal
• Ex: NaCl
•
Polyatomic
ion
is a group of atoms that acts as a single
atom.
• have an overall electrical charge.
• atoms are held together by covalent bonds.
• If there is more than one polyatomic ion in a
molecule, the polyatomic ion is written in
parentheses.
. End with ite or ate
EX: SO32- Sulfite (one less Oxygen than the
ate) (Charge will be same)
SO42- Sulfate (Charge will be same)
3 Exceptions in the
polyatomic ions
• Ammonium polyatomic cation that
not ending with “ite” or “ate” ending
NH+4 - Ammonium
NH+3 -Ammonia
• Cyanide CN• Hydroxide OH-
Ionic compound with
polyatomic ions
• Contain a metal and a polyatomic ion
• Contain three or more elements
• Or contain a poly atomic cation and a
nonmetal
• Or contain two polyatomic ions.
• Ex: Na2 SO4
( 3 elements)
• Ex: Ca(SO4)2 (more than one
polyatomic ions, you must use a
parenthesis around it)
Covalent Compounds
(Molecular compounds)
• Always going to be nonmetals
combined with nonmetals
• Identify or name using prefix for the
number of atoms.
• Form molecules
• Weaker than ionic compounds
Prefix for covalent
compound
•
•
•
•
•
•
•
•
•
•
Mono -1
Di-2
Tri-3
Tetra-4
Penta-5
Hexta-6
Septa-7
Octa-8
Nano-9
Deca-10
Chemical bonds
• are the force that join two or more
atoms.
• A stable compound occurs.
• a net (total) attractive force
between the atoms .
Two types of bonds
• Covalent bond: one or more pairs of
electrons are shared by two atoms.
• Ionic bond: one or more electrons
from one atom are removed and
attached to another atom.
• resulting in positive and negative
ions which attract each other.
Covalent Bonds
• involve the sharing of a pair of
valence electrons by two atoms
Ionic Bonds
• one or more atoms lose electrons
and other atoms gain
Ionization energy
• The amount of energy used to
remove an electron is known as the
ionization energy
• Varies from element to elements
• Energy increases from left to
right(less reactive)
• Energy decreases from top to
bottom(easy to remove the electron,
so it will be more reactive)
• Ex: K is more reactive than Na
Crystal Lattices
• formed by an ionic compound. the
particles are arranged in a repeating
pattern
• The attractions of the positive and
negative ions keeps a fixed position in
a frame work (lattice)
• Ex:LiCl
(metal)
CHARGE OF ATOM
neutral
Na
11
(nonmetal)
CHARGE OF ATOM
neutral
Cl
17
(metal)
CHARGE OF ATOM
neutral
Na
11
(nonmetal)
CHARGE OF ATOM
neutral
Cl
17
(metal)
CHARGE OF ATOM
neutral
Na
11
(nonmetal)
CHARGE OF ATOM
neutral
Cl
17
(metal)
CHARGE OF ATOM
neutral
Na
11
(nonmetal)
CHARGE OF ATOM
neutral
Cl
17
(metal)
CHARGE OF ATOM
neutral
Na
11
(nonmetal)
CHARGE OF ATOM
neutral
Cl
17
(metal)
CHARGE OF ion
positive
(cation)
[Na]+
11
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
[Cl]1-
17
(anion)
(metal)
CHARGE OF ion
positive
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
(cation)
[Na]
1+
11
[Cl]
1-
17
(anion)
(metal)
CHARGE OF ion
positive
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
(cation)
[Na]
1+
11
(anion)
[Cl]
1-
17
(metal)
CHARGE OF ion
positive
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
(cation)
[Na]
1+
11
(anion)
[Cl]
1-
17
(metal)
CHARGE OF ion
positive
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
(cation)
[Na]
1+
11
(anion)
[Cl]
1-
17
(metal)
CHARGE OF ion
positive
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
(cation)
[Na]
1+
11
(anion)
[Cl]
1-
17
(metal)
CHARGE OF ion
positive
(nonmetal)
CHARGE OF ion
negative
Ionic Bond
(cation)
[Na]
1+
11
(anion)
[Cl]
1-
17
What is a diatomic
molecule?
• is made up of two atoms of the
same element
• is usually held together by a covalent
bond.
• Most gaseous elements form
diatomic molecules.
7 diatomic molecules
• Hydrogen( H2),
• Oxygen ( O2),
• Nitrogen (N2),
• Fluorine (F2),
• Chlorine(Cl2),
• Bromine (Br2)
• Iodine(I2)
Metallic Bonds
• Is the attraction between a
metal cation and the shared
electrons that surround it
• More valance electrons in a
metal-stronger the metallic
bond