Match the following people with their
contributions to atomic theory?
___1. Law of Conservation of Mass
___2. The discovery of the electron
___3. Law of Definite Proportions
___4. The discovery of the nucleus
___5. The planetary Model of the atom
A.
B.
C.
D.
E.
Bohr
Rutheford
Proust
Thomson
Lavoisier
Match the following people with their
contributions to atomic theory?
_E_1. Law of Conservation of Mass
_D_2. The discovery of the electron
_C_3. Law of Definite Proportions
_B_4. The discovery of the nucleus
_A_5. The planetary Model of the atom
A.
B.
C.
D.
E.
Bohr
Rutherford
Proust
Thomson
Lavoisier
According to the Law of Conservation of
Mass, what is the missing mass of the
compound in the equation below?
𝐶𝑎(𝑂𝐻)2 + 2HCl → 𝐶𝑎𝐶𝑙2 + 2 𝐻2 O
18g
+ 17.8g =
27g + ___g
According to the Law of Conservation of
Mass, what is the missing mass of the
compound in the equation below?
𝐶𝑎(𝑂𝐻)2 + 2HCl → 𝐶𝑎𝐶𝑙2 + 2 𝐻2 O
18g
+ 17.8g =
27g + _8.8_g
In a chemical equation, mass can neither be created or
destroyed. Therefore the total mass on one side of a chemical
equation must equal the mass on the other side.
What is the name of the Law that explains
why the two molecules below are different?
CO and CO2
What is the name of the Law that explains
why the two molecules below are different?
CO and CO2
The Law of Definite Proportions
This law states that for every compound, there is a definite
proportion of atoms in the compound.
Although CO and CO2 both consist of carbon and oxygen, the ratio of
those two atoms in each compound determines the identity and
properties of the each compound.
In the diagram below, would the cathode ray be
attracted or deflected from the magnet above?
+
-
+
In the diagram below, would the cathode ray be
attracted or deflected from the magnet above?
+
-
+
Because cathode rays are made of electrons which are negatively
charged, cathode rays will be attracted to the positive end of a
magnet.
What was the name of Thomson’s model
of the atom and what did it consist of?
What was the name of Thomson’s model
of the atom and what did it consist of?
The “Plum Pudding” model
What was the name of Rutherford’s model
of the atom and what did it consist of?
What was the name of Rutherford’s model
of the atom and what did it consist of?
The “Nuclear” Model
How did Rutherford discover the nucleus
of the atom?
How did Rutherford discover the nucleus
of the atom?
He shot positively charged alpha particles at a sheet of gold
foil and most of the time the particles were observed to go
right through the foil. Sometimes, the particles’ path was
bent and only about 0.01% of the time, particles bounce
back. From these observations Rutherford concluded that:
1. The atom was made of mostly empty space.
2. The center of the atom was dense (compact) and
positively charged.
Dalton proposed that atoms of one element
were identical, but different from atoms of
another element.
Why was he wrong? Explain.
Dalton proposed that atoms of one element
were identical, but different from atoms of
another element.
Why was he wrong? Explain.
It is true that atoms of one element are different from atoms of
another element. However, atoms of the same element can also be
different by the number of neutrons that they contain. For example,
all carbon atoms are not the same. There are 3 naturally occurring
ISOTOPES of carbon: carbon-12, carbon-13 and carbon-14. Each
contains the same number of protons and electrons but a different
number of neutrons.
Fill in the table
Element
Protons
28
Neutrons
Electrons Mass number
60
Isotope
Fill in the table
Element
Protons
Neutrons
Electrons
Mass number
Isotope
Nickel
28
32
28
60
Ni-60
Why is the mass of an atom roughly equal
to the mass of only the protons and
neutrons in the atom?
Why is the mass of an atom roughly equal
to the mass of only the protons and
neutrons in the atom?
The mass of an electron is only about 1/2000 the mass of
either a proton or neutron and therefore contributes very
little to the mass of the atom.
Determine the atomic mass of
potassium using the following data.
Isotope
Mass
% Abundance
K-39
38.963708
93.20
K-40
39.963999
0.012
K-41
40.961825
6.73
Determine the atomic mass of
potassium using the following data.
Isotope
Mass
% Abundance
(changed to abundance)
Multiply Mass
times abundance
K-39
38.963708
0.9320
36.31417586
K-40
39.963999
0.00012
0.00479568
K-41
40.961825
0.0673
2.756730823
Atomic Mass of Potassium = 39.07570236*
* Add the numbers in the last column to get the mass of the element
Which isotope contributes more to the
mass of Iridium, Ir-191 or Ir-193?
Ir-191 has a mass of 190.960603 and Ir-193 has a mass of 192.962942.
The atomic mass of Iridium is 192.22
Ir(191) 190.960603 37.30 Ir(193) 192.962942
62.70
Which isotope contributes more to the
mass of Iridium, Ir-191 or Ir-193?
Ir-191 has a mass of 190.960603 and Ir-193 has a mass of 192.962942.
The atomic mass of Iridium is 192.22
The atomic mass of iridium is closest to the mass of Ir-193. In
fact, Ir-193 makes up about 67% of all iridium atoms whereas
only 33% of iridium atoms are of the Ir-191 type.
How many atomic orbitals can be found in
each of the following sublevels?
s
p
d
f
How many atomic orbitals can be found in
each of the following sublevels?
s
p
d
f
1
3
5
7
Each orbital holds 2 electrons. So in any s sublevel there are 2
electrons, 6 electrons in a p sublevel, 10 electrons in a d
sublevel and 14 electrons in a f sublevel.
What is the electron configuration of
arsenic?
What is the electron configuration of
arsenic?
1s22s22p63s23p64s23d104p3 or [Ar] 4s23d104p3
The first configuration is written in long-hand notation. The
second configuration is written using a noble gas to account for
all of the electrons through the 3p. Noble gases can be used in
this way because their configurations are very stable.
How many valence electrons does arsenic
have?
How many valence electrons does arsenic
have?
Valence electrons are the outermost electrons in an atom.
The number of valence electrons can be determined two ways for most
atoms.
1. Look at the electron configuration and find all of the electrons that
exist at the highest energy level. Those are the valence electrons.
[Ar] 4s23d104p3 = 5 valence electrons
2. Find the column number that the element is in. For elements that are
in the last 6 columns of the table, only look at the ones digit in the
column number. Arsenic is in column 15, so it has 5 valence electrons.
What information does a Lewis dot
structure contain?
What is the structure for arsenic?
What information does a Lewis dot
structure contain?
What is the structure for arsenic?
The Lewis dot structure contains the symbol for the element and
its valence electrons. There can only be a maximum of 8 valence
electrons for any atom, 2 on each side of the element symbol.
Make sure to only pair up electrons for atoms that have more
than 4 valence electrons.
Which of the following graphs shows the
relationship between wavelength and
frequency?
Between energy and frequency?
A
B
Which of the following graphs shows the
relationship between wavelength and
frequency?
Between energy and frequency?
In A, when energy and frequency are plotted on a
graph, the variables will change in the same direction
which will give a positive slope.
A
In B, when wavelength and frequency are plotted on a
graph, the variables will change in the opposite direction
which will give a negative slope.
B
Which wave has the shortest wavelength,
the highest frequency and the highest
energy?
A
B
C
Which wave has the shortest wavelength,
the highest frequency and the highest
energy?
A
B
C
Wave C has all of those characteristics
How is an atomic emission spectrum
different from the electromagnetic
spectrum?
How is a continuous spectrum different
from an atomic emission spectrum?
The continuous spectrum contains all wavelengths
and frequencies of visible light.
The atomic emission spectrum corresponds to
the wavelength and frequencies of light given
off by the electrons of specific atoms when
they become excited.
What is the frequency of a wave that has a
wavelength of 3 x 10-10m?
What is the energy of the same wave?
What is the frequency of a wave that has a
wavelength of 3.0 x 10-10m?
c=ln
n=c/l
𝑣=
3.0 𝑥 108
3.0 𝑥 10−10
= 1.0 x 1012/s
What is the energy of the same wave?
E=hn
E=6.626 x 10-34J.s x 1.0 x 1012/s = 6.626x 10-22J