Chapter 4 Vocabulary:
1) nucleus- _________________________________________________________________________
___________________________________________________________________________________
2) proton- __________________________________________________________________________
___________________________________________________________________________________
3) electron- _________________________________________________________________________
___________________________________________________________________________________
4) neutron- _________________________________________________________________________
___________________________________________________________________________________
5) atomic number- ___________________________________________________________________
___________________________________________________________________________________
6) mass number- ____________________________________________________________________
___________________________________________________________________________________
7) isotopes- ________________________________________________________________________
___________________________________________________________________________________
8) energy levels- _____________________________________________________________________
___________________________________________________________________________________
9) electron cloud- ____________________________________________________________________
___________________________________________________________________________________
10) orbital- _________________________________________________________________________
___________________________________________________________________________________
11) electron configuration- ____________________________________________________________
___________________________________________________________________________________
12) ground state- ____________________________________________________________________
___________________________________________________________________________________
Chapter 4, Lesson 1: Studying Atoms
Name: _______________________ Hour: ______
Introduction (Page 100)
Give an example of using Indirect Evidence: ______________________________________________________
Ancient Greek Models of the Atom (Page 100)
Democritus-believed that matter was made up of ____________________ that cannot be ________________
He called them ____________________ which means ________________________
He thought different ____________________________ that had different properties
Aristotle-did not think there was a limit to the number of times an atom could be _______________________
Thought all substances were composed of _________________________________ (See Figure 1)
Most people accepted Aristotle’s model, but he was wrong
Dalton’s Atomic Theory (Page 101)
Dalton was born in ________________________ and was a _________________________
His interest in predicting the weather led him to study the _______________________________
He based his evidence on way gases exert _______________________ on walls of container
He correctly concluded gases were made of __________________________________________
Evidence for Atoms (Page 101)
He gathered evidence by measuring __________________________ that combine to form compounds
He figured out that the ____________ of masses of elements in the compound was always the same
In other words, he figured out that compounds have a _____________________________________
Dalton’s Theory (Page 102)
He developed a theory that attempted to explain why elements in a compound ___________________
Proposed that all matter was made up of particles called__________________which can’t be divided
4 MAIN POINTS OF DALTON’S THEORY:




All elements composed of ______________ that were indivisible
Atoms of same element have same _________________ (are identical)
o And that Different elements have different masses
Compounds contain atoms of more than one ____________________
In compounds, atoms combine in the same way (and always a whole number ratio)
Each type of atom was represented by a ______________________________ with a different mass
His theory explained data from many experiments, so the theory became _______________________
Over time, scientists found that not all of Dalton’s ideas were __________________________
They did not discard his theory, but instead ________________ it to take new discoveries into account
Thompson’s Model of the Atom (Page 102)
Introduction
Objects with like charges ________________, while opposite charges ____________________
Some charged particles can _______________ from one location to another
This flow of charged particles is called ___________________________
JJ Thompson used an electric current to learn more about _______________________
Thompson’s Experiments (Page 103)
Thompson used an electric current to learn more about atoms
The device he used is called a cathode ray tube
Tube filled with
gas at low pressure
Glowing beam of particles
Source of current
When the source of current was turned on, a glowing beam appeared in the tube
Thompson hypothesized that the beam was a stream of ____________________________
To test his hypothesis, he placed charged plates on either side of the tube
He observed that the beam was repelled by the ___________ plate and attracted by the _________
Evidence for Subatomic Particles (Page 103)
Thompson concluded that the particles had a ___________________ charge
He also realized that the particles had come from _____________________________
He had 2 pieces of evidence to support his theory:
1) particles were same regardless ___________________
2) particles were lighter than ______________________
Thompson’s discovery changed the way scientists thought about atoms
Before his experiments, scientists thought atoms were solid and couldn’t be divided
Thompson’s experiments provided the FIRST evidence that __________________________________
Thompson’s Model (Page 103)
The particles Thompson discovered were negative but atoms are ________________ (have no charge)
He knew there must be some positive charges in there as well to balance out the negative
In Thompson’s model, the negative charges were __________________ throughout the atom
The model is called the ______________________________ (named for a traditional English dessert)
We could call it the chocolate chip ice cream model (Long-Live Blue Bell!!! LOL)
Rutherford’s Atomic Theory (Page 104)
Rutherford discovered that ________________ emitted positively charged particles (alpha particles)
He asked his student to find out what happened when alpha particles passed through a sheet of gold
Based on Thompson’s model, he predicted the particles would _____________________________
The Gold Foil Experiment (Page 104)
Rutherford aimed a narrow beam of __________________________ at the gold
The screen around the gold lit up when struck, allowing scientist to see the path of the alpha particles
The results were unexpected—more particles deflected and some even bounced _________________
Expected results
Actual results
Rutherford’s Discovery of the Nucleus (Page 105)
Realized the alpha particles which were deflected had come close to another ____________________
He realized the positive charge was not evenly spread but concentrated at the____________________
He called the area where the positive charge was the ______________________________
The nucleus is a dense, positively charged mass located at the ________________________________
According to Rutherford’s model (known as the Nuclear Model) all the positive charge is at the center
Name: ____________________________________ Date: ___________________ Hour: _____________
LESSON 4-1 DISCUSSION QUESTIONS:
1. Why do scientists have to use indirect evidence to study atoms?
2. Describe the two different ancient Greek models of matter:
3. Describe Dalton’s evidence for the existence of atoms.
4. What did Dalton notice that all compounds have in common?
5. List the main points of Dalton’s atomic theory.
6. Why did scientists accept Dalton’s Theory but not the idea proposed by the Greek philosophers?
7. What evidence did JJ Thompson provide about the structure of the atom?
8. What evidence did Thompson have that his beam contained negatively charged particles?
9. Why was Dalton’s model changed after Thompson’s experiment?
10. What did Rutherford observe about the structure of the atom?
11. If you saw a beam of particles bend towards a negative plate, what might you conclude?
12. Which portions of Dalton’s model were accurate and what portions needed to be revised?
Lesson 4.2: Atomic Structure
Properties of Subatomic particles
The three subatomic particles are ________________________________________________
Proton-_______________________________________________________________
Who discovered and named them? ________________________________________
What is the charge of each proton? ________________________________________
Electron- _____________________________________________________________
Who first detected these particles? ________________________________________
What is the charge of each electron? _______________________________________
Neutron- _____________________________________________________________
Who designed the experiment that showed they exist? ________________________
What is the charge of each neutron? _______________________________________
Atomic Number and Atomic Mass
Atomic Number- _____________________________________________________________
What makes all atoms of the same element unique? _________________________________
Can atoms that have a different number of protons be atoms of the same element?_______
In an atom, there is no charge. What does that tell you about the number of electrons an
atom has? __________________________________________________________________
Ions are atoms that have gained or lost an ______________ and developed a charge.
If an atom has lost an electron, it has a ______________ charge
If an atom has gained an electron, it has a _______________ charge
Mass Number- _______________________________________________________________
How is the mass number calculated? _____________________________________________
How would you find the number of neutrons using mass and atomic numbers?
___________________________________________________________________________
Why don’t the electrons count towards the mass number? ___________________________
What do you call the decimal number that is shown on the periodic table of elements below
the name of the element? ______________________________________________________
How is this number found? _____________________________________________________
What is the difference between the mass number and the average atomic mass?
___________________________________________________________________________
Practice with Atomic Numbers and Mass Numbers:
8
O
Oxygen
Atomic Number
Chemical Symbol
Element Name
Average Atomic Mass
15.999
30
Atomic #: __________
__
Atomic Mass: ________
Zinc
65.39
Mass #: _______
# of Protons: _________
# of Neutrons: ________
# of Electrons: ________
3
Atomic #: __________
Li
Atomic Mass: ________
_______
6.941
Mass #: _______
# of Protons: _________
# of Neutrons: ________
# of Electrons: ________
53
Atomic #: __________
12
Atomic #: __________
__
Atomic Mass: ________
Mg
Atomic Mass: ________
Mass #: _______
# of Protons: _________
Mass #: _______
# of Protons: _________
# of Neutrons: ________
_______
126.905
# of Electrons: ________
24.305
79
Atomic #: __________
14
Atomic #: __________
__
Atomic Mass: ________
__
Atomic Mass: ________
Iodine
Gold
196.967
Mass #: _______
# of Protons: _________
# of Neutrons: ________
_______
# of Electrons: ________
28.086
# of Neutrons: ________
# of Electrons: ________
Mass #: _______
# of Protons: _________
# of Neutrons: ________
# of Electrons: ________
Isotopes- _________________________________________________________________________
All atoms of the same element have the same number of ____________________
An isotope has the same number of protons but a different number of ________________
How does the existence of isotopes disprove part of Dalton’s Atomic Theory? ____________
It is hard to distinguish between isotopes. Which element is an exception? _______________
Uranium- 235 and Uranium-237 are isotopes. How are they similar & how are they different?
Isotope Notation
For Nitrogen-15 (This is called hyphen notation):
The number 15 is the ___________________________
The number 7 (found on the periodic table) is the ___________________________
How many neutrons does Nitrogen-15 have? ________________________________
Write Nitrogen-17 using isotope notation:
Practice: Write in isotope notation and find number of protons, neutron, and electrons.
YOU WILL NEED A PERIODIC TABLE—DON’T FORGET: ATOMIC # = # of PROTONS
Hyphen Notation
Isotope Notation
#p
#n
#e
Zinc-66
Helium-4
Uranium-235
Potassium-40
Write the following in Hyphen Notation and Isotope Notation:
Description of Isotope
The atom with 12 protons and 12 neutrons:
The atom with 6 protons and 7 neutrons:
The atom with 79 protons and 117 neutrons:
The iodine atom with 72 neutrons:
The copper atom with 34 neutrons:
Hyphen Notation
Isotope Notation
Ions: _____________________________________________________________________
Atoms are NEUTRAL by definition—the number of protons EQUALS the number of electrons
If an atom gains or loses an electron, it becomes CHARGED and is called an ION
Example: An atom of Chlorine has 17 protons and 17 electrons, but an ion of Chlorine will
usually gain one electron and become _________________________ charged
Find the following:
# of Protons: _________ # of Electrons: __________ Ion Symbol: __________
Practice: Fill in the blanks in the table below:
Ion Name
# Electrons Lost
or Gained
# Protons
# Electrons
Ion Symbol
Practice: Given the Ion Symbol, find the number of protons and electrons:
Ion Symbol
# of Protons
# of Electrons
Review:
If atoms have a different # of protons, they are _________________________________
If atoms have same # protons, but different # neutrons, they are ______________________
If atoms have same # protons, but different # electrons, they are ______________________
Lesson 4.3: Modern Atomic Theory
BOHR’S MODEL
Bohr’s Model shows the electrons ______________________________________________________
How was Bohr’s Model different from Rutherford’s? ________________________________________
How do electrons move in Bohr’s model? _________________________________________________
According to Bohr’s Model, what happens to electrons as they gain or lose energy?
___________________________________________________________________________________
An electron in an atom can move from one energy level to another when it _____________ electrons
Electrons can move up two levels if _____________________________________________________
The size of the jump depends on the ____________________________________________________
Evidence for the existence of energy levels includes the facts that scientists can measure:
The energy gained when ______________________________________________________________
The energy lost when _________________________________________________________________
The movement of electrons between energy levels explains __________________________________
The light is emitted as a result of ________________________________________________________
The unique energy levels of different elements create ______________________________________
ELECTRON CLOUD MODEL
Like earlier models of the atom, Bohr’s model was _________________________________________
Bohr was correct about _______________________________________________________________
Bohr was incorrect about ______________________________________________________________
Scientists use the electron cloud to describe the ___________________________________________
The cloud is most dense in the area where ________________________________________________
ATOMIC ORBITALS
An orbital is a region of space around the nucleus where ____________________________________
An electron cloud is a good approximation of how __________________________________________
The lowest energy level has only ____________________ orbital
Each orbital contains ____________________________ electrons
ELECTRON CONFIGURATIONS
An electron configuration is ___________________________________________________________
The most stable configuration is the one in which __________________________________________
When electrons gain energy they move to an _______________________ state which is LESS stable
than the _____________________ state where electrons have the lowest possible energy levels.
Chapter 4 STUDY GUIDE
1) According to ________________ all matter was made up of particles called atoms which were indivisible
2) According to _________________ all matter was composed of four elements- earth, air, fire, and water
3) __________’s Atomic Model said atoms were solid spheres with a predictable mass for a given element
4) Name the four main points of Dalton’s Model:
5) JJ Thompson is credited with the discovery of ____________________________ (namely the electrons)
6) How did Thompson’s discovery change the model of the atom? _________________________________
7) What experiment did he use to discover this info? ________________________________________
8) Why was the beam attracted by the positive end of the magnet? _______________________________
9) Thompson’s model was called the ________________________________________
10) Rutherford discovered the _______ and called the positively charged particles found there ________.
11) What experiment did he use to discover this info? _________________________________________
12) What caused the alpha particles to bounce straight back? ___________________________________
13) How did his discovery change the model of the atom? _______________________________________
14) Name the three subatomic particles: ______________________________________________________
15) How does the mass of an electron compare to that of protons and neutrons? ____________________
16) Name 3 properties that you can use to distinguish a protons, neutron, and electrons:
17) The atomic number of an element is ALWAYS equal to the number of _____________________
18) In a NEUTRAL ATOM of an element the number of (positive) protons equals the number of _________
19) Atoms of same element have the same number of ______ but can have different numbers of ________
20) The nuclei of different isotopes contain different numbers of ____________________________.
21) The mass number is equal to the SUM of the ___________ and ____________
22) The difference between Oxygen-17 and Oxygen-18 is the ___________________________________
***What is the same about those isotopes of Oxygen? __________________________________
23) How do you determine number of neutrons when given the mass number and the atomic number? ______
24) If germanium-70 has a mass number of 70 and an atomic number of 32, how many neutrons? ________
25) If an atom has a mass number of 31 and 16 neutrons, how many protons would it have? ____________