Download atomic numbers

FOUNDATIONS OF
MATTER NOTES
Matter
► MATTER-
mass
has _____________
and
space
occupies ____________________.
► All matter consists of tiny particles called
atoms
________________.
►
►
►
fixed shape and volume
SOLID- has a _______
LIQUID- has a definite
_______ volume but takes the shape of
the container
no
GAS- has ___________fixed
volume or shape
Solid
Gas
Liquid
characteristic
PHYSICAL PROPERTIES- a __________________
of a
substance that can change without the substance
becoming a different substance
ability
► CHEMICAL PROPERTIES- the _____________
of a
substance to change into a different substance
form of a
► PHYSICAL CHANGE- a change in the _________
substance, but not in its _________________
nature;
chemical
chemical bonds are not broken in a physical change
► CHEMICAL CHANGE- the change of substances into
reorganizationof
_____________
substances through a ______________
other
chemical reaction
the atoms; a ________________________
►
► Matter
Prezi:
http://prezi.com/kbcpimj8z80o/?utm_campa
ign=share&utm_medium=copy
Learning Check
► Element,
Compound or Mixture?
Water
Oxygen
Sodium chloride (table salt)
Sea water
Gold
Soil
ranch dressing
Soda
Milk
Air
Steel
granite rock
Hydrogen
sugar dissolved in water
Kool-Aid™
Potassium
filtered apple juice
fresh squeezed lemonade
Arsenic
Carbon dioxide
Compound
Element, diatomic
Compound
Heterogeneous mix.
Element
Heterogeneous mix.
Heterogeneous mix.
Heterogeneous mix.
Heterogeneous mix., emulsion/suspension
Homogeneous mix., solution
Homogeneous mix., solution, alloy
Heterogeneous mix.
Element, diatomic
Homogeneous mix., solution
Homogeneous mix., solution
Element
Homogeneous mix., solution
Heterogeneous mix., suspension
Element
Compound
Separation Techniques
►
DISTILLATION
- a method of
separating the
components of a
liquid
___________
that depends on
the differences in
the ease of
vaporization of
the components
► FILTRATION-
a
method of
separating the
components of a
mixture
containing a
solid
____________
and a
liquid
____________.
►
►
CHROMOTOGRAPHY
– a method of
separating
components of a
heterogeneous mixture
by their polarities.
Ex. Separating
components of ink on
paper
Separating a Mixture Lab
Formulas of Compounds
1. Symbols a.
b.
used to represent the element
first letter is capital, second letter (if necessary) is lower case
C = carbon
2. Subscripts –
a.
b.
Ca = calcium
small number to the lower right of the element symbol
represents the relative composition of each element in a compound
or molecule
CO2 = 1 carbon, 2 oxygen
3. Superscripts –
a.
b.
Cr = chromium
Ba(NO3)2 = 1 barium,
2 nitrogen, 6 oxygen
small number to the upper right of the symbol/formula
used to represent the charge of an ion
Ca+2
Br-1
NO3-1
4. Coefficients –
a.
b.
big number in front of the formula
indicates the number of compounds present
3 CO2 = 3 carbon dioxide or 3 carbon, 6 oxygen
Modern Concept of the Atom
The atom is made of three elementary particles.
Protons
positive charge
1. ____________
2. mass is almost equal to the mass of the
neutrons
___________
nucleus
3. Found in the _____________
4. Number of protons is __________
equal to the
atomic number
Neutrons
no or neutral charge
1. ____________
2. mass is __________________________
than
slightly greater
the proton
nucleus
3. Found in the _____________
4. Neutrons act as the glue that holds together
the nucleus.
- too few or too many neutrons can result
in nuclear instability and then radioactivity
Electrons
negative charge
1. ____________
2. mass is ___________________
2000 x less
than the proton
3. Found moving around the nucleus
at near the speed of light.
- sometimes called
_______________________
or
charge cloud
electron cloud
______________________
4. The Quantum Mechanical Model
- currently accepted model of the
atom (Chapter 11)
- for now we will use the Bohr
model, rings of electrons
neutral
Atoms are always _____________
► Isotopes
same
 Atoms with the __________
number of protons but
different
a ______________
number of neutrons
►


A different number of neutrons results in a different
mass.
Mass of individual atoms is determined by only the
protons and neutrons, the electrons are too light to
be significant.
protons + ___________
neutrons
Mass Number = __________
►

Isotope notations
►
►
40K
means that potassium has a mass number of 40
Potassium-40 also means a mass number of 40
A
Z
X
X = Element symbol
Z = Atomic number = # of protons in nucleus = # on periodic table
A = Mass number = # of protons + # of neutrons in nucleus
Element Symbo Atomic
l
Number
Carbon
Chlorine
Sodium
14C
6
35Cl
17
23Na
11
Mass
Number
Number
of
Protons
Number
of
Neutrons
Number
of
Electrons
6
14
6
8
6
17
35
23
17
11
18
17
12
11
11
Ions
Electron
When an atom gains or loses an __________________
it takes on a charge
and becomes an ion
the charge is determined by the #e- (negative charge) when compared to
#p+ (positive charge)
Calcium ions (Ca+2) has 20 p+ and 18 e- because the calcium atom lost 2
electrons
Fluoride ions (F-1) has 9 p+ and 10 e- because the fluorine atom gained one
electron
Positive Ions are called _______________
Cations
Negative Ions are called _______________
Anions
Element
Symbol
Number
Atomic
Mass
of
Number Number
Protons
Carbon
Chlorine
Sodium
14C-4
6
35
17
23
11
Cl-1
Na+1
6
17
11
14
35
23
6
17
11
Number
of
Neutrons
Number
of
Electrons
8
18
10
18
12
10
Early History of the ATOM
1.
Democritus (Greek Philosopher 460 B.C.)
Atoms are indivisible and everywhere
2. Dalton’s Atomic Theory
Atoms
Elements are made of tiny particles called ____________.
All atoms of the same element are ________________
.
identical
(Not really but close, isotopes)
Atoms of a given element are ________________
from those of any
different
other element.
Atoms of one element will combine with other atoms to form
compounds
_________________
.
Atoms are __________________
during chemical reactions; they are
indivisible
never created or destroyed. (He was not talking about nuclear
reactions)
Atomic Theory Timeline
Average Atomic Mass
►
Average Atomic Mass – the weighted average of the
masses of the isotopes of an element
Every element is composed of several naturally occurring
isotopes of that element-each with its own atomic mass
► A weighted average of the percentage of each isotope that
exists versus the atomic mass of each isotope is used to
calculate the atomic mass that appears on the periodic table.
►
Step 1) Change each percent abundance into a decimal weight.
Step 2) Multiply each atom’s mass by its decimal weight to get
the contribution for each isotope.
Step 3) Add all the contributions together to
get the average
atomic mass.
►
Has units of amu, atomic mass unit.
Average Atomic Mass =
Σ [(isotope mass) * (percent abundance of isotope)]
100
Example 1: The element copper occurs naturally as
69.17% of copper-63 with a mass of 62.9296 amu
and 30.83% of copper-65 with a mass of 64.9278
amu. What is the average atomic mass of copper?
Example 2: The atomic weight of gallium is 69.72 amu. The masses of the
naturally occurring isotopes are 68.9257 amu and 70.908 amu for 69Ga
and 71Ga respectively. Calculate the % abundance of each isotope.
Learning Check
Naturally occurring element consists of 75.78% atoms with a mass of 34.969
amu and 24.22% atoms with a mass of 36.966 amu.
Calculate the average atomic mass.
b) Based on the average atomic mass, what is the element?
Nuclear Reactions
Nuclear Reactions vs.
Normal Chemical Changes
NUCLEUS
NUCLEAR REACTIONS involve the ___________.
PROTONS and NEUTRONS are
REARRANGED in the nucleus, releasing a
______________
tremendous amount of energy.
“Normal” CHEMICAL REACTIONS involve
_____________,
not protons and neutrons.
ELECTRONS
Why do Nuclear
Reactions happen?
Nuclear Instability
The stability of a nucleus is dependent on
the neutron to proton ratio (N:Z)
For light nuclei (elements 1-20), the N:Z ratio should be 1:1
For heavy nuclei (elements above 20), the N:Z ratio should be 1.5:1
Atoms that lie either above
or below the band of stability
will undergo nuclear decay
to achieve stability.
Atoms that lie ABOVE the
band of stability have TOO
MANY NEUTRONS.
Atoms that lie BELOW the
band of stability have TOO
MANY PROTONS.
Two Types of Nuclear Reactions
Fission nucleus splits into smaller nuclei
___________–
to become more stable.
►atomic bombs (like those dropped on Hiroshima
and Nagasaki).
►Nuclear reactors
Fusion
___________–
nuclei fuse into one larger
nucleus to become more stable.
►the sun (or any star)
►Creating elements larger than Element 92 (U)
►Elements
1-92 occur naturally in the universe
Half-Life
Using the known half-life of elements to determine the age
of artifacts
► Radioisotope: an unstable, radioactive atom that decays
over time to become more stable.
► Half-Life: the
amount of time
that it takes half
of a radioisotope
sample to decay.
►
Ex 1) Assuming a half-life of 1599 years, how many
years will be needed for the decay of 15/16 of a given
amount of radium-226?
Total
Time
HalfLife
0
Ex 2) The half-life of radon-222 is 3.824 days. How
much time must past for 25% of a given amount of
radon to remain?
1
2
3
4
Ex 3) The half-life of radium-224 is 3.66 days. What
was the original mass of radium-224 if 0.0800g
remains after 7.32 days?
5
6
Fraction of
Radioactive
Atoms
Remaining
Fraction of
Radioactive
Atoms
Decayed
Nuclear Decay
RADIATION: particles & electromagnetic waves
released during nuclear decay.
Most radiation comes from the SUN & COSMIC
RADIATION.
Nuclear Decay Products
4
2
He
or 4
2

ALPHA particle: α
is a Helium-4 nucleus
has POOR PENETRATING ability – can
be stopped by PAPER.
Nuclear Decay Products
0
-1

or
BETA particle: β
e
0
-1
aka. ELECTRON or NEGATRON
has a negative charge
A NEUTRON emits a negatron and then BECOMES a PROTON
POSITRON

0
+1
or
e
0
+1
aka. ANTIELECTRON
has a positive charge
A PROTON emits a positron and then BECOMES a NEUTRON
Penetrate BETTER than ALPHA particles, but can be stopped by an
ALUMINUM sheet.
Nuclear Decay Products
0
0
g
GAMMA ray: γ
is a gamma PHOTON.
has GREAT PENETRATING ability – can ONLY be
stopped by LEAD or CONCRETE.
is very DANGEROUS.
can be released with other forms of decay.
Nuclear Decay Products
1
0
n
NEUTRON: n
can be ABSORBED or RELEASED during a nuclear
reaction
combine with other nuclei in secondary reactions,
which could create harmful radiation.
has GREAT PENETRATING ability – can be stopped
by CONCRETE.
Nuclear Decay Products
Nuclear Equations
Reactants
Yield
Products
Nuclear equations must be BALANCED.
The sum of the MASS NUMBERS and the
sum of the ATOMIC NUMBERS must be
the SAME on both sides of the equation.
Alpha Decay Reaction
238
92
U
234
90
Th +
4
2
4
Mass # Change: decrease by ___
2
Atomic # Change: decrease by ___
He
Beta Decay Reaction
14
6
C
14
7
N +
0
-1
e
no change
Mass # Change: ______________
1
Atomic # Change: increase by ___
Electron Capture Reaction
51
24
Cr +
0
-1
e
51
23
V
no change
Mass # Change: ___________
1
Atomic # Change: decrease by ___
Positron Emission Reaction
49
24
Cr
49
23
V +
0
+1
e
no change
Mass # Change: _____________
1
Atomic # Change: decrease by ___