Transcript Catalyst 10/13

Catalyst: Complete the Chart
Element
Barium
Phosphorous
Nitrogen
Symbol
Group #
# Valence
Electrons
Ion Formed
Lewis Dot
Structure
Ba2+
Ba
15
5
Hint: According to the octet rule, atoms lose or gain electrons,
forming ions, in order to get a full outer shell with 8 electrons. If
the atom loses electrons it is a positive cation and if it gains
electrons it is a negative anion.
Catalyst: Answers
Element
Symbol
Group #
# Valence
Electrons
Ion Formed
Barium
Ba
2
2
Ba2+
Phosphorous
P
15
5
P3-
Nitrogen
N
15
5
N3-
Lewis Dot
Structure
Hint: According to the octet rule, atoms lose or gain electrons,
forming ions, in order to get a full outer shell with 8 electrons. If
the atom loses electrons it is a positive cation and if it gains
electrons it is a negative anion.
TODAY’S OBJECTIVE:
BONDING!!!!
SWBAT Differentiate between
IONIC &COVALENT BONDS
A.K.A.: Why don’t you blow up when you eat sodium chloride since sodium
is a highly reactive metal and chlorine is an extremely poisonous gas??
Agenda
• Catalyst/HW Check (10)
HW Review (10)
Part 1: Ionic Compound Formula Review: Kris-Kross
Method (20)
PART 2: Ionic vs. Covalent Compounds
• Ionic vs. Covalent Notes (20)
• Ionic vs. Covalent Lab (40)
• Ionic vs. Covalent Conductivity Demo (10)
• Closing (5)
Homework Answers
1.
2.
3.
4.
5.
6.
7.
8.
Having equal amounts of positive and negative charge is called
electroneutrality.
An electrically charged group of two or more bonded atoms that functions
as a single ion is a polyatomic ion.
Collections of cations are never found without a similar number of anions
(or sometimes electrons) nearby to effectively neutralize the charges.
The names for cations come from the element from which they are
formed.
When an element forms two or more positive ions, the ions are
distinguished by using roman numerals to indicate the charge.
The name of a simple anion is formed by changing the ending of the
element name to –ide.
A subscript is a whole number written below and to the right of an
element’s symbol, and it is used to denote the number of atoms in a
formula.
Any chemical compound that is composed of oppositely charged ions is
called an ionic compound.
More HW Answers
9) K+ + Br- → KBr
10) Ba2+ + F- → BaF2 (2 F- to balance 2+ charge)
11) Sn4+ + O2- → SnO2 (2 O2- to balance 4+)
12) Cs2+ + Br- → CsBr2 (2 Br- to balance 2+)
The rest of the problems are coming up as
practice…
Writing Ionic Compound Formulas
Notes
Kris Kross Method!
2+
3Ca As
Ca3As2
Just kris kross the
positive and the
negative charges
1+
1Na Cl
4+
2Pb O
NaCl
Pb2O4
Practice Problems
• What ionic compound is formed?
1. Cobalt (II) and Bromine
2. Mercury(I) and Sulfur
3. Aluminum and Iodine
Hints:
•
Periodic table groups tell us how many valence electrons
•
Draw Lewis structure
•
Metals lose electrons to form positive cations
•
Nonmetals gain electrons to form negative anions
•
Compounds must be neutral (equal # of + and – charges)
Part 2! Ionic vs. Covalent Bonds
• Make a Chart in your notes that looks like this:
Ionic Bonds
Covalent Bonds
Ionic vs. Covalent Bonds
• Bond Strength = the energy needed to
break the bonds between atoms in a
compound.
Ionic vs. Covalent Bonds
Ionic Bonds
Covalent Bonds
Atoms in ionic compounds are held
together by ionic bonds.
Atoms in covalent or molecular
compounds are held together by
covalent bonds.
Ionic bonds are stronger (more bond
strength)
Covalent bonds are weaker (less
bond strength)
Ionic vs. Covalent Bonds
Ionic Bonds
Covalent Bonds
Transfer of electrons
Sharing of electrons
Ionic vs. Covalent Bonds
Ionic Bonds
Covalent Bonds
Crystal Lattice
Molecules
Water (H2O) molecules
Lithium Chloride (LiCl)
crystal lattice
Ionic vs. Covalent Bonds
Ionic Bonds
Covalent Bonds
Metal and nonmetal
Nonmetal and nonmetal
Ionic vs. Covalent Bonds
Ionic Bonds
Covalent Bonds
Solid at room temp.
Solid, Liquid or Gas at
room temp.
Ionic vs. Covalent Bonds
Ionic Bonds
Covalent Bonds
Conducts electricity
when dissolved
Does not conduct
electricity
Investigation: Ionic vs. Covalent
• You will work in groups of 4. (2 groups per table)
• Lab WS is due at end of class
• Safety! Do not put any test substances near your
eyes or mouth.
• Clean Up: Pour liquids down the sink and solids in
the trash.
• Objective: Conduct four tests on four substances.
Predict whether they are ionic or covalent.
• Ms. Boon will run the conductivity test.
Exit Slip
• What is the formula for a compound
between: Ca & F?
• Compare at least one difference between
ionic & covalent compounds?
• Does the compound MgBr2 share electrons
or transfer them between the atoms?
3 Types of Bonding
**IONIC
How are ELECTRONS are
Bonds
transferred
Formed? between ions (1
Type of
Bond
Formed
Who’s
Involved
?
*COVALENT METALLIC
Electrons are shared
between atoms.
steals, 1 gives)
Solid Crystals with Usually liquid or
repeating patterns solid
of (+) and (-) ions
METAL + NONMETAL
Special
When dissolves in
Properties H20, conducts
electricity
“Sea of Electrons”
Spread all over
between atoms of
the same element.
Solid metal
NON-METAL +
NON-METAL
METAL AND
METAL
Does not conduct
electricity
Very good conductors
of electricity on their
own!
Practice- Ionic or covalent?
•
•
•
•
•
•
•
•
SH6
KCl
H3C3O2
N2
CsBr
HF
CaCl2
H2
•
•
•
•
•
•
•
MgCl2
NH3
Li2S
Cl2
H2O
Na3P
BaS