Putting Atoms Together
Download
Report
Transcript Putting Atoms Together
PUTTING ATOMS TOGETHER
Chapter 7
TERMINOLOGY
Molecule – two or more atoms of the same or different elements
that are chemically joined together in a unit.
nitrogen
20%
• Ex. Air = roughly 80% _______________
molecules, _____
oxygen molecules, and trace amounts of H2O and
CO2
TERMINOLOGY
notation
that
indicates
the
type
and
number
Chemical Formula –
of atoms in a pure substance
above/after in chemistry
•Superscript - small numbers written ____________,
usually indicates a charge Mg2+
below/after tells us how many
• Subscript – small number ___________,
atoms there are O2 = 2 oxygen atoms
Diatomic Elements – Elements that exist as molecular elements
consisting of 2 atoms.
*7
MOLECULAR
COMPOUNDS
Sharing is caring!
What do we call rxn’s that release
energy/heat?
What do we call rxn’s that require
it?
TERMINOLOGY
Molecular Compounds –
Compound consisting of two
or more different elements
with neutral charges that are
bonded together.
non-metal
• Involves two _______________
(includes hydrogen) elements
joining together and sharing
valence electrons to fill
their ________
energy level
their outer __________________
(shell).
A simulation of the reaction:
2H2 + O2
2H2O
Means electrons “LEAN” or
migrate towards one molecule
creating partial + and - charges
Forces that hold atoms together
Represent “potential” energy
Illustration to the right
hydrogen
shows two __________
molecules and a single
oxygen
_______ molecule.
Hydrogen wants to have a
full valence
________ shell (first shell
2
can hold a max. of __)
meanwhile the oxygen
atom also wants to have a
full valence shell (2nd shell
8 Therefore a
can hold __).
sharing of electrons
____________________
occurs.
2H + 1O
H2O
A key aspect of molecular compounds is the fact they are
dependent____
on arrangement
______________________
____________________. Only certain
combinations in __________
are found in nature.
fixed _______________________
amounts
Ex. O2 = Oxygen Gas, meanwhile O3 = Ozone
•The above example highlights the fact that a change in
configuration
______________________________________
dramatically changes the
compound and how it affects us.
______________________________________________
These molecules can be drawn as
Bohr-Rutherford
__________________________________________
diagrams or as
Lewis dot diagrams
____________________________________
with the shared pair of electrons
represented by a _____, 2 pairs by a ______, or 3 sets of shared
electrons by _____. The most that will ever be shared is 3.
IONIC COMPOUNDS
TERMINOLOGY
Compound consisting of a positively charged (cation) and
• Def. negatively charged (anion) ion.
metal
non-metal
• Involves a ___________
+ a _____________
joining
giving away its ___________
valence
together, with the metal _____________
non-metal taking them.
electrons and the __________
_________
a particle that has a + or - charge
Def. Ion –_________________________________
2 forms
Anion = Negative
1.) _________
Cation = Positive 2.) _________
WHY DOES THE METAL ALWAYS GIVE
AWAY ITS VALENCE ELECTRONS AND
THE NON-METAL ALWAYS TAKE THEM?
• Think about this silently (use your notes or
textbook as a reference)
ANSWER
• It is easier for a metal to give up 3 or 4
electrons than try to take enough to fill its
valence shell.
• For non-metals, they generally only need 1 or 2
extra’s to fill their shells, so it is easier for them
to take 2 than give up 6.
+ Charge
(Protons)
- Charge
(Electron)
Ionic charge
Sodium
Sodium
Chlorine
Chlorine
Atom, Na
Ion, Na+
Ion, Cl-
Atom, Cl
DRAW DIAGRAM FROM TEXT
(pg. 260)
• Copy the Bohr-Rutherford
• Create a Lewis Dot Diagram
Sodium Ion, Na+
Chlorine Ion, Cl-
HW Q 1-8 on page 261
PERIODIC TABLE WORKSHEET
REVIEW
Metals are located on the left side of the
1. _______
non-metals located on the right
periodic table, with __________
staircase that
side. They are separated by a “________”
touches the __________.
metalloids
periods and tell us
2. Horizontal rows are known as ________
shells an element
the number of Energy
______ levels
_____ or ______
has.
Families or groups are vertical ________
columns on the
3. ________
periodic table and tell us how many valence
electrons an element has.
_________
4. ATOMS have the same number of Protons as
atomic _______,
number so their charge is neutral, this
they do ______
charge
information is detailed in the ______.
charge because
5. IONS have a positive or negative _______
they have given up their valence
_______ electrons
_________ or taken
valence electrons from an atom of another element in
order to fill/empty their outer energy shell.
cations (think the t looks
6. Positive ions are known as _______
anions (has two
like a +) while negative ions are called _______
n’s for negative).
MAGNESIUM ATOM
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Draw a Bohr-Rutherford Diagram
LITHIUM ATOM
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Draw a Lewis-Dot Diagram
ARGON ATOM
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Number of Neutrons =
• Draw a Lewis Dot diagram
FLUORINE ATOM
ION REVIEW
a) An ION of fluorine is going to mimic (look like) an atom
Neon
of ______.
b) An ION of beryllium is going to mimic an atom of
Helium
__________________.
phosphorus has to gain 3 electrons to
c) An ION of ____________
-3
mimic argon. Its ionic charge will be ____.
d) An ION of Aluminum
_________ has to give up 3
electrons in order to mimic an atom of neon. Its
+3
charge will be ___.
gain ___
2 electrons to
e) An Ion of Oxygen has to ____
neon Its ionic charge will be ___.
-2
mimic _____.
CALCIUM ATOM
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
OXYGEN ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
CHLORINE ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
ALUMINUM ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
POTASSIUM ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
QUESTIONS FROM READING
• How do atoms become more stable?
• When metals mix with another metal is it called an ________.
• When metals mix with non-metals it is called an __________
compound.
• What happens with the electrons in these compounds?
• When two non-metals mix it is called an ____________
compound.
• What happens with the electrons in these compounds?
IONIC COMPOUNDS
Names & Formulas
REVIEW
Compound consisting of a positively charged (cation) and
• Def. negatively charged (anion) ion.
metal
non-metal
• Involves a ___________
+ a _____________
joining
giving away its ___________
valence
together, with the metal _____________
non-metal taking them.
electrons and the __________
_________
a particle that has a + or - charge
Def. Ion –_________________________________
2 forms
Anion = Negative
1.) _________
Cation = Positive 2.) _________
NAMING
Ionic compounds are easily identified by the presence
metal (first term). Any time you see a metal as
of a ___________
the first term, you should automatically be thinking
NUMERICAL
IONIC! Additionally, there is never a __________________
reference in the compound name (so no
PREFIXES
_________________).
The nice thing about naming Ionic
DO NOT need to worry about
molecules is we __________
numbers (subscripts).
Example K2O
1)Determine how many elements (each capital letter
represents a new element) are present in the compound
2
(_______)
and locate them on the periodic table. Is there
a metal..? If so it must be a Ionic Compound.
2) Identify which of the elements is the metal (it must go
Potassium
first). __________________
3) Identify the non-metal element (it goes 2nd).
Oxygen
____________________
4) Write the name of the metal, than the name of the nonmetal (but change the ending of the non-metal to
Potassium _____________
oxide
“IDE”). ___________
Try these…
Li2O
Lithium oxide
CaS
Calcium sulphide
MgF2
Magnesium flouride
Be3P2
Berylium phosphide
NaCl
K3N
Sodium chloride
Potassium nitride
LiBr
Na2O
Lithium bromide
Sodium oxide
WRITING CHEMICAL FORMULAS FOR
IONIC COMPOUNDS
given/taken and electrical
Since the electrons are ____________
charges
_______ are present we need to reference the
Periodic Table in order to determine how many of
each element there is going to be.
THE CHARGES MUST BALANCE
____________________________!
Step 1: Locate the elements in the Periodic Table- ensure
one is a metal, and one is a non-metal. Write down their
chemical symbol.
Step 2: Determine the “charge” each element carries when
its forms an ionic bond (remember: STABLE)
Step 3: Backcross the “charges“ to SUBSCRIPTS for each
+1 -2
element
Rb O
Ex.
+1 -2
Rb O
Rubidium “charges it up” _____
_____ “backcross it down”
fluoride
Rb2O1
Compound
Sodium
chloride
Magnesium
nitride
Calcium
fluoride
Francium
phosphide
CHARGE
Na+1 Cl-1
Mg+2 N-3
Ca+2 F-1
Fr+1 P-3
FORMULA
NaCl
Mg3N2
CaF2
Fr3P