Transcript Atomic Models

Atomic Models
100 points –Performance
Due Friday, February 26th
Thomson's Model
(Plum Pudding Model)
• Do I need to represent , electrons, protons,
and neutrons?
• Common mistake: Do not represent positive
sphere as being “solid”.
Thomson’s Model
(Plum Pudding Model)
Rutherford's Model
• Do I need to represent , electrons, protons,
and neutrons?
• Small dense positive nucleus and a lot of
empty space.
• Common mistake- represent protons and
neutrons in the nucleus and not enough
empty space.
Rutherford's Model
Bohr Model
• Do I need to represent , electrons,
protons, and neutrons?
• Bohr models will be of a rare isotope.
• Common mistake- Groups that choose a
larger atom don’t come talk to me about
the fourth “shell”.
Bohr Model
Quantum Mech. Model
• Do I need to represent , electrons, protons, and
neutrons?
• QMM will need to be of the most common isotope
and ion for your element.
• Choose to represent orbital model or electron cloud
model
• Common Mistake- Don’t ask for help in determine
the most common ion or write it on their key. Make
sure to clarify whether it the orbital model or
electron cloud model on their key or poster.
Quantum Mech. Model
Key and Poster
• Key should be able to stand on their own or
nicely hang from your model.
• Information Poster can be hand written or
types on 8 by 11 sheet of paper.
• This is an out of class assignment, however
you can come in for this IP and next to build
your model. I will have some supplies you can
use.
• You can use the next 10 minutes to plan with
your group.
• Due Friday February 26th
End of Day
Key Concept 20: 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 21: 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 22: 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
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.
Isotope- Neutrons
• Isotopes containing more neutrons have a
greater mass.
• Isotopes have the same chemical behavior.
• Key Concept 23: 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 24: 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 25: 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
Mass of Atoms (cont.)
• Key Concept 26: The average atomic
mass of an element is the weighted
average mass of the isotopes of that
element.
Practice Problems
• Key Concept 27: 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
• Key Concept 28: 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.
Misconception
•There is only one type of
carbon atom
Ground-State Electron Configuration (cont.)
Ground-State Electron Configuration (cont.)
• Noble gas notation uses noble gas
symbols in brackets to shorten inner
electron configurations of other elements.
Now Lets Practice
Write the Nobel Gas Configuration for the
following:
• Calcium
• Aluminum
• Bromine
Valence Electrons
• Key Concept 29: Valence electrons are
defined as electrons in the atom’s
outermost orbitals—those associated with
the atom’s highest principal energy level.
Circle Valence Electrons
• Calcium
• Aluminum
• Bromine
Valence Electrons
• Key Concept 30: Electron-dot structure
(Lewis Structure) consists of the element’s
symbol representing the nucleus, surrounded
by dots representing the element’s valence
electrons.
Lewis Structure
• Calcium
• Aluminum
• Bromine
Valence Electrons (cont.)
Key Concept 30:
Now Lets Practice
Identify the number of valence electrons and
draw their Lewis Structure
• Magnesium
• Argon
Draw their Lewis Structure
• Phosphorus
• Iodine
Valence Electrons
• The number of valence electrons and the dot
structure follow a pattern based on which column
the element is in