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Chap 4 Bell -Ringers
The
Structure
of the Atom
The Atom has a
Structure
Chapter 1The 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 1The Science of Chemistry
Chapter 2Matter 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 1The Science of Chemistry
Chapter 2Matter 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 1The Science of Chemistry
Chapter 2Matter and Atoms
Temperature, Energy, and Heat
Physical and Chemical Change
What we’ve seen so far…
Chapter 1The Science of Chemistry
Chapter 2Matter and Atoms
Temperature, Energy, and Heat
Physical and Chemical Change
How can we explain the
properties and behaviors
observed so far?
Chapter 1The Science of Chemistry
Chapter 2Matter and Atoms
Chapter 3Temperature, 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
Democritus
Atomism
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
Democritus
Atomism
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
Democritus
Atomism
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
Democritus
Atomism
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
Democritus
Atomism
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
Democritus
Atomism
460 – 370 BC
Dalton
“Modern”
atomic theory
Crookes
Cathode rays
Cathode rays
must be negative.
J.J. Thomson
discovers the
electron
Today1808 1870 1897 1910
Democritus
Atomism
460 – 370 BC
Dalton
“Modern”
atomic theory
Crookes
Cathode raysThomson
Discovery
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
nitrogen8 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-13 Carbon-14
# protons
# neutrons
Mass
number 12 13 14
Name Carbon-12 Carbon-13 Carbon-14
# protons
# neutrons
Mass
number 12 13 14
Name Carbon-12 Carbon-13 Carbon-14
# protons 6 6 6
# neutrons
Mass
number 12 13 14
Name Carbon-12 Carbon-13 Carbon-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
Crookes
Cathode raysThomson
Discovery
of the electron
Rutherford
Discovery
of the nucleus
Democritus
Atomism
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% 0% 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
0% 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
0% 0% 0%0%0%
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% 0% 0%0%0%
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% 0% 0%0%0%
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%0%
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% 0% 0%0%0%
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% 0% 0%0%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% 0% 0%0%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% 0% 0% 0%0%0%0%
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.
..
0% 0% 0% 0%0%0%0%
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.
..
0% 0% 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% 0% 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% 0%0%0%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 le
vels
Mass
num
ber
Ele
ctro
magne
tic fo
rce
Strong n
uclea
r fo
rce
0% 0% 0% 0%0%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
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
atom1. 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?
6
6
6
6 p+
6n0
2 4
14
6
How many
protons?
How many
electrons?
How many
neutrons?
Draw a atomic
model for this
element?
6
6
8
6 p+
8n0
2 4
7
3
How many
protons?
How many
electrons?
How many
neutrons?
Draw a atomic
model for this
element? 3 p+
4n0
3
3
4
2 1
14How many
protons?
How many
electrons?
How many
neutrons?
Draw a atomic
model for this
element? 7 p+
7n0
7
7
7
2 5
Na-23How many
protons?
How many
electrons?
How many
neutrons?
Draw a atomic
model for this
element?
11
11
12
11 p+
12n0
2 8 1
238How many
protons? 92
How many
neutrons?
238-92 = 146
Be-9
atomic number?
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%0%
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%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9
number of neutrons?
1 2 3 4 5 6 11
0% 0% 0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9
number of energy levels?
1 2 3 4 5 6 11
0% 0% 0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
14Si
valence electrons?
1 2 3 4 5 6 11
0% 0% 0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
7N
valence electrons?
1 2 3 4 5 6 11
0% 0% 0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
Be-9
number of electrons in the first
energy level?
1 2 3 4 5 6 11
0% 0% 0% 0%0%0%0%
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 11
17Cl
number of electrons in the first
energy level?
1 2 3 4 5 6 11
0% 0% 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
1. Who discovered the electron?
2. Electrons in the outer energy are
called?
3. The columns in the periodic table
are called
• NEED YOUR PERIODIC TABLE
FOR THIS ONE
Find SULFUR (atomic # 16)
• How many valence electrons
does it have?
• Which orbital is being filled?
1. Element or compound??
Hydrochloric acid HCl
2. What element is most closely
related to Bromine?
3. What does the group # tell us?
• 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”?
A
B
C
Which orbital is represented by :
A? B? C?s d p
Which 2 orbitals are we most concerned with
because of valence electrons? s and p
A
B
C
Which are the metals?
Nonmetals?
A
B
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