chap 4 bell -ringers. the structure of the atom the atom has a structure
TRANSCRIPT
Chap 4 Bell -Ringers
The Structure
of the Atom
The Atom has a Structure
Chapter 1 The Science of Chemistry
What we’ve seen so far…- Chemistry is about discovering and understanding natural laws using the scientific method
- Energy cannot be created nor destroyed
- Matter can be mixtures or substances. The smallest unit of a pure substance is an element.
- Each element is a type of atom, and they can be arranged in a periodic table.
- Atoms come together to form compounds. Atoms with an electric charge are known as ions.
Chapter 1 The Science of Chemistry
Chapter 2 Matter and Atoms
What we’ve seen so far…
- Temperature is a measure of kinetic energy.
- Heat is thermal energy.
- Heat gain and heat loss can cause phase changes, as molecules are rearranged.
Chapter 1 The Science of Chemistry
Chapter 2 Matter and Atoms
Chapter 3 Temperature, Energy, and Heat
What we’ve seen so far…
- In a physical change molecules are rearranged. In a chemical change atoms are rearranged to make new substances.
- Chemical reactions can be endothermic or exothermic.
- Many reactions occur in aqueous solution, and some elements are more reactive than others.
Chapter 1 The Science of Chemistry
Chapter 2 Matter and Atoms
Temperature, Energy, and Heat
Physical and Chemical Change
What we’ve seen so far…
Chapter 1 The Science of Chemistry
Chapter 2 Matter and Atoms
Temperature, Energy, and Heat
Physical and Chemical Change
How can we explain the properties and behaviors observed so far?
Chapter 1 The Science of Chemistry
Chapter 2 Matter and Atoms
Chapter 3 Temperature, Energy, and Heat
Physical and Chemical Change
How can we explain the properties and behaviors observed so far?
Answers can be found inside
the atom
92 different types of atoms!
Each of the elements is a unique type of atom.
Atoms are made from smaller particles!
electrons
protons
neutrons
How did scientists come up with this?
Atoms are made from smaller particles!
electrons
protons
neutrons
It started a long time ago…Today460 – 370 BC
Democritus
Beginning of Atomism
You cannot divide something in half forever.
The smallest piece of matter is called an atom.
How do you find out about something you can’t see?
Think of the conservation of mass labs, distilled wood, even flame test lab
Think of experimentation of the Copper, HCl and Zinc lab
Think of the Rutherford marble tossing lab
Bellringer
When scientists wanted to find out what an atom was, they were not able to look directly at what the atom was made of. They had to make inferences from the results of many different experiments. It was like trying to describe a picture, such as the one on the next slide, with only small portions visible.
Bellringer, continued
1. Write four sentences describing what you can see of the above picture.
2. What information or parts of the picture would make your descriptions more accurate without revealing the entire picture?
Scientists contributing
DALTON
BOHR
CHADWICK THOMSON
de BROGLIE
RUTHERFORD
Today1808
DemocritusAtomism
460 – 370 BC
Dalton’s Postulates
1. All elements are made of tiny indivisible particles called atoms.
Over 2,000 years later John Dalton comes up with the first “modern” atomic theory.
Today1808
DemocritusAtomism
460 – 370 BC
Dalton’s Postulates
1. All elements are made of tiny indivisible particles called atoms.
2. All atoms of the same element are the same, but different from atoms of
every other element.Over 2,000 years later John Dalton comes up with the first “modern” atomic theory.
Today1808
DemocritusAtomism
460 – 370 BC
Dalton’s Postulates
1. All elements are made of tiny indivisible particles called atoms.
2. All atoms of the same element are the same, but different from atoms of
every other element.
3. Chemical reactions rearrange atoms but do not create, destroy, or convert atoms from one element to another.
Over 2,000 years later John Dalton comes up with the first “modern” atomic theory.
Today1808
DemocritusAtomism
460 – 370 BC
Dalton’s Postulates
4. Compounds are made from combining atoms in simple whole number ratios.
1. All elements are made of tiny indivisible particles called atoms.
2. All atoms of the same element are the same, but different from atoms of
every other element.
3. Chemical reactions rearrange atoms but do not create, destroy, or convert atoms from one element to another.
Over 2,000 years later John Dalton comes up with the first “modern” atomic theory.
Another kind of light?Today1808 1870
DemocritusAtomism
460 – 370 BC
Dalton“Modern”
atomic theory
William Crookes invents a tube in which virtually all the gas has been removed.
Under high voltage, a ray was emitted from the cathode end of the tube.
It started a long time ago…Today1808 1870 1897
DemocritusAtomism
460 – 370 BC
Dalton“Modern”
atomic theory
CrookesCathode rays
Cathode rays must be negative.
J.J. Thomson discovers the electron
Today1808 1870 1897 1910
DemocritusAtomism
460 – 370 BC
Dalton“Modern”
atomic theory
CrookesCathode rays
ThomsonDiscovery
of the electronErnest Rutherford discovers the nucleus
It started a long time ago…
The size of the atom comes
mostly from the space occupied by
the electrons
The mass of the atom comes mostly from the nucleus
Size and mass
Charges in the atom
electronsprotons
neutrons
A complete atom has a charge of zero
Charges in the atom
Charges in the atom
electronsprotons
neutrons
What happens when you change the number of protons?
You obtain a different element!
6 protons in carbon
7 protons in nitrogen
8 protons in oxygen
The number of protons is also called
the atomic number for that element.
The electron cloud
Except for mass, virtually every property of atoms is
determined by electrons, including size and chemical bonding
Electrons are very light and fast.
They are not organized along orbits around the nucleus.
electronsprotons
neutrons
What happens when you change the number of neutrons?
Atomic number
Neutrons act as “glue.” They hold protons together in the nucleus.
mass number: total number of protons and neutrons in a nucleus.
Mass number = 6 p + 6 n = 1212C
“carbon-12”
Mass number
Name
# protons
# neutrons
Mass number
Name Carbon-12 Carbon-13Carbon-14
# protons
# neutrons
Mass number 12 13 14
Name Carbon-12 Carbon-13Carbon-14
# protons
# neutrons
Mass number 12 13 14
Name Carbon-12 Carbon-13Carbon-14
# protons 6 6 6
# neutrons
Mass number 12 13 14
Name Carbon-12 Carbon-13Carbon-14
# protons 6 6 6
# neutrons 6 7 8
isotopes: atoms or elements that have the same number of protons in the nucleus but different number of neutrons.
Two lithium isotopes in nature
Atomic mass
How can lithium have 0.941 neutrons?
Number of neutrons for each of 100 lithium atoms randomly sampled from nature
It’s an AVERAGE mass!
Isotope periodic table (first 4 rows)
There must be a force that keeps the
nucleus together
Forces in the atom
In the nucleus Electrons
Electrons repel each other, but don’t “fall into” the nucleus because they are
in constant motion.
Electrons form bonds between atoms.
Forces in the atom
The strong nuclear force attracts protons to protons, neutrons to
neutrons, and protons to protons
Today1808 1870 1897 1910460 – 370 BC
Dalton“Modern”
atomic theory
CrookesCathode rays
ThomsonDiscovery
of the electron
RutherfordDiscovery of the nucleus
DemocritusAtomism
electronsprotons
neutrons
The size of the atom comes mostly from the electrons
The mass of the atom comes mostly from the nucleus
Who coined the term atom in 4 BC?
Dal
ton
Dem
ocritu
s
Ruth
erfo
rd
Bohr
Thom
son
0%
100%
0%0%0%
1. Dalton
2. Democritus
3. Rutherford
4. Bohr
5. Thomson
Who stated that elements are made of indivisible spheres called atoms?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
100%
0% 0%0%0%
1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who discovered the atom was divisible and had subatomic parts?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
5%0%
71%
10%14%
1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who discovered the electron?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
0%
17%
48%
4%
30%
1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who discovered that atoms are mostly empty space?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
0% 4% 0%0%
96%1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who discovered the nucleus?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
0% 0% 0%0%
100%1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who discovered the proton in the nucleus?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
0%
9%
0%5%
86%1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who stated that electrons are located in fixed energy levels?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
0%
62%
0%
38%
0%
1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Who discovered the neutron?
Dal
ton
Chad
wic
k
Ruth
erfo
rd
Bohr
Thom
son
0%
96%
0%4%0%
1. Dalton
2. Chadwick
3. Rutherford
4. Bohr
5. Thomson
Center of a atom, contains most of the atom’s mass
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Ener
gy le
vels
Mas
s num
ber
Ele
ctro
mag
neti.
..
0%5%
0% 0%5%
0%
91%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
Positively charged particle that exists in the nucleus
of an atom.
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Ener
gy le
vels
Mas
s num
ber
Eel
ctro
mag
neti.
..
96%
0% 0% 0%0%0%4%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Eelctromagnetic force
Particle with no charge that exists in the nucleus of an atom
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Ener
gy le
vels
Mas
s num
ber
Ele
ctro
mag
neti.
..
4%
96%
0% 0%0%0%0%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
The least massive of the three subatomic particles which also carries an negative net charge.
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Ener
gy le
vels
Mas
s num
ber
Ele
ctro
mag
neti.
..
0% 0%
100%
0%0%0%0%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
Describes how electrons are arranged around an atom
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Ener
gy le
vels
Mas
s num
ber
Ele
ctro
mag
neti.
..
0% 0% 0%4%
0%
96%
0%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
The force that holds the positively charged nucleus
together is called
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Energ
y lev
els
Mass
num
ber
Ele
ctro
magne
tic fo
rce
Stro
ng nucl
ear f
orce
0% 0% 0%
82%
18%
0%0%0%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
8. Strong nuclear force
The force that holds the atom together is called
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Energ
y lev
els
Mass
num
ber
Ele
ctro
magne
tic fo
rce
Stro
ng nucl
ear f
orce
0% 0% 0%
12%
88%
0%0%0%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
8. Strong nuclear force
The total number of protons and neutrons in the nucleus of an
atom
Pro
ton
Neu
tron
Ele
ctro
n
Nucl
eus
Ener
gy le
vels
Mas
s num
ber
Ele
ctro
mag
neti.
..
0% 0% 0% 0%
100%
0%0%
1. Proton
2. Neutron
3. Electron
4. Nucleus
5. Energy levels
6. Mass number
7. Electromagnetic force
C-12
How many protons?
How many electrons?
How many neutrons?
Draw a atomic model for this element?
C14
6
How many protons?
How many electrons?
How many neutrons?
Draw a atomic model for this element?
Li 7
3
How many protons?
How many electrons?
How many neutrons?
Draw a atomic model for this element?
N 14
How many protons?
How many electrons?
How many neutrons?
Draw a atomic model for this element?
Na-23 How many protons?
How many electrons?
How many neutrons?
Draw a atomic model for this element?
U238
How many protons?
How many neutrons?
Be-9atomic number?
1 2 3 4 5 6 11
0% 0% 0% 0%0%4%
96%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9 number of protons?
1 2 3 4 5 6 11
0% 0% 0% 0%0%0%
100%1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9 number of electrons?
1 2 3 4 5 6 11
0% 0% 0% 0%0%4%
96%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9number of neutrons?
1 2 3 4 5 6 11
0% 0% 0% 0%0%
100%
0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9number of energy levels?
1 2 3 4 5 6 11
0%
96%
4%0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
14Sivalence electrons?
1 2 3 4 5 6 11
0% 0%
13%
0%0%0%
88%1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
7Nvalence electrons?
1 2 3 4 5 6 11
0%4%
0% 0%0%
96%
0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9number of electrons in the first
energy level?
1 2 3 4 5 6 11
0%
100%
0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
17Clnumber of electrons in the first
energy level?
1 2 3 4 5 6 11
0%
100%
0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Complete the energy levels …
• # of Protons?• # electrons?
• # e’ in 1st orbital?• # e; in 2nd orbital?• # of valence e’ ?
NITROGEN
7
2
5
5
7
1. Who discovered the electron?
2. Electrons in the outer energy are called?
3. The columns in the periodic table are called
JJ Thomson
Valence electrons
Groups
• NEED YOUR PERIODIC TABLE
FOR THIS ONE
Find SULFUR (atomic # 16)• How many valence electrons
does it have?• Which orbital is being filled?
63rd
1. Element or compound?? Hydrochloric acid HCl
2. What element is most closely related to Bromine?
3. What does the group # tell us?
Compound
Fluorine / Chlorine
The # of valence electrons
• 1. Who did the gold-foil experiment?
• 2. Who stated that elements are made of atoms?
• 3. What does the period # tell us?
• 4. Who created the term “atomos”?
Rutherford
Dalton
# of the energy level being filled
Democritus
A
B
C
Which are the metals?
Nonmetals?A
B