Download Isotope

Key Concept 21: The 3 I’s of Chemistry
Identity- Protons
Isotopes- Neutron
Ions- Electron
Identity- Protons
• Each element contains a unique positive
charge in their nucleus.
• Key Concept 22: The number of protons in
the nucleus of an atom identifies the element
and is known as the element’s atomic
number.
Isotope- Neutrons
• All neutral atoms of a particular element
have the same number of protons and
electrons but the number of neutrons in the
nucleus can differ.
• Key Concept 23: Atoms with the same
number of protons but different numbers
of neutrons are called isotopes.
• 1913
• Fredrick Soddy discovered isotopes.
“certain elements exist in two or more forms which
have different atomic weights but which are
indistinguishable chemically.”
Isotope- Neutrons
Misconception
•There is only one type of
carbon atom
Greek Philosophers (cont.)
What were the errors in the Dalton’s Atomic Theory?
Mass of Atoms
• One atomic mass unit (amu) is defined as
1/12th the mass of a carbon-12 atom.
• One amu is nearly, but not exactly, equal to
one proton and one neutron.
End of Day
Isotope- Neutrons
• Isotopes containing more neutrons have a
greater mass.
• Isotopes have the same chemical behavior.
• Key Concept 24: The mass number is the
sum of the protons and neutrons in the
nucleus.
Isotope- Neutrons
• The relative
abundance of
each isotope is
usually constant.
Isotope- Neutrons
Key Concept 25: Isotope Format
Atomic Mass
Atomic Number
Element (X)- Atomic Mass
What is this atom mass?
11
5
Boron- 11
Room # 169429
12
6
What is this atom’s mass?
14
How many neutrons does this atom have?
?
6
What would this atom’s mass be if it has 7 neutrons?
4
How many neutrons does this atom have?
Ion- Electron
• Key Concept 26: An ion is an atom or bonded
group of atoms with a positive or negative
charge.
Ion- Electron
• Cation – positively charged ion
• Anion – negatively charged ion
• Polyatomic Ions
“Poly” = many
“atomic” = atoms
Ion = charged
– Polyatomic ion - many atoms bonded together
having an overall charge
Look at your Periodic Table
How many electron does this ion have?
+
What type of ion is this?
+1
How many electron does this ion have?
+2
4±
What type of ion is this?
-4
How many electron does this ion have?
How many electron does this ion have?
+2
How many electron does this ion have?
-
The Basics
The Foundations
The Building Blocks
of Chemistry
Call It Whatever You Want
They Are Must Knows
You must be able to:
Read a periodic table and use to key to determine:
Understand isotope format: lithium-6
6Li
Understand how to write ions:
Na1+
verse lithium-7
7Li
Fe2+
1.
2.
3.
4.
What is my name?
What is my atomic number?
What is my average atomic mass?
(Pick one of my isotopes on the left side of the card). What is the
atomic mass of that particular atom?
5. How many protons do I have (in the isotope)?
6. How many neutrons do I have (in isotope)?
7. How many electrons do I have if I am neutral(in isotope)?
8. (Pick an ion of the right side of the card) How many protons and
electrons do I have?
9. (Consider that I am the previous chosen isotope in question 4 and
a neutral atom) What happens to me if I gain a
p+ (I become _________.)
no ( I become _________.)
e- ( I become _________.)
10. What happens to me if I lose a
p+ (I become _________.)
no ( I become _________.)
e- ( I become _________.)
End of Day
Today
• Get with your lab partners and complete the
10 questions for becoming an atom with two
more cards.
• Rapid Fire
• What you need to know
• Pass out Practice Problems B
• Note card research
1.
2.
3.
4.
What is my name?
What is my atomic number?
What is my average atomic mass?
(Pick one of my isotopes on the left side of the card). What is the
atomic mass of that particular atom?
5. How many protons do I have (in the isotope)?
6. How many neutrons do I have (in isotope)?
7. How many electrons do I have if I am neutral(in isotope)?
8. (Pick an ion of the right side of the card) How many protons and
electrons do I have?
9. (Consider that I am the previous chosen isotope in question 4 and
a neutral atom) What happens to me if I gain a
p+ (I become _________.)
no ( I become _________.)
e- ( I become _________.)
10. What happens to me if I lose a
p+ (I become _________.)
no ( I become _________.)
e- ( I become _________.)
Rapid Fire
9. What happens to me if I gain a
p+ (I become _________.)
no ( I become _________.)
e- ( I become _________.)
10. What happens to me if I lose a
p+ (I become _________.)
no ( I become _________.)
e- ( I become _________.)
Happy Atoms
• Key Concept 27: A happy ATOM is an
ATOM that has its orbitals (shell) all full.
In order to become full that atom must
gain or lose electrons.
• Most atoms form compounds in order to
be happy.
What do you need to know??
• Determining the number of electrons is the
most difficult.
• You need to be able to answer these type of
questions when talking about elements.
– How many electrons does a neutral atom of Ca
have?
– What is the most common ion Oxygen will form?
– How many electrons does Br -1 have?
• Practice Problems B
End of day
Mass of Atoms (cont.)
• Key Concept 27: The average atomic
mass of an element is the weighted
average mass of the isotopes of that
element.
Practice Problems
you need a stamp
• Key Concept 28: The four isotopes of lead and
its abundances are: Pb-204, 1.37%; Pb-206,
26.26%; Pb-207, 20.82%; and Pb-208, 51.55%.
Calculate lead’s approximate atomic mass.
Practice Problems
you need a stamp
• Key Concept 29: Calculate the estimated
average atomic mass of neon if neon exists
naturally as 90.92% neon-20, 0.257% neon-21,
and 8.82% neon-22.
Calculating Atomic Mass
• Move into shoulder partners
• Work through the worksheet together.
• If you get done before it is time to move on
get out practice problems B and complete.
Blank Sheet of Paper… answer these
1.Tell me how many electrons are in these 3 ions
1.K+
2.P-3
3.Be+2
2.List the discovery's and importance of Bohr, Rutherford,
Thomson, Dalton
3.Complete the Electron Configuration (long and Nobel Gas)
for Al, Se and C
4.What is the average atomic mass and what is the element
1.X-23.985,78.70%;
2.X-24.986 10.13%;
3.25.983 11.17%
Reminder
• Reminder Prove it Quiz on Wednesday.
• Quiz 2 you need to take by
• Quiz 3 will be available on
Review
• Draw Bohr model diagrams for the following
elements:
– Fluorine
– Chlorine
– Carbon
– Silicon
• For the following elements list the electron
configuration.
–Oxygen
–Cesium
–Krypton
• For the following elements list the noble-gas
notation electron configuration
–Boron
–Phosphorus
–Lead
• How many electrons are in each orbital
–S
–D
–P
–F
• How do you correctly write an
element in isotope format?
• How many protons and electrons are in the
following Ions
– Cl– Al+3
– Mg+2
– O-2
• Draw the Lewis dot structure for the following
atoms:
– a. hydrogen
– b. helium
– c. boron
• Titanium has five common isotopes: 46Ti
(8.0%), 47Ti (7.8%), 48Ti (73.4%), 49Ti (5.5%),
50Ti (5.3%). What is the average atomic mass
of titanium?
• Calculate the average atomic mass of
magnesium using the following data for three
magnesium isotopes.
Isotope
mass (u) relative abundance
Mg-24
23.985
0.7870
Mg-25
24.986
0.1013
Mg-26
25.983
0.1117