Download Atomic Structure

Atomic Structure
Do you know your atomic
structure?
Basic Unit of Matter
•ATOM
• Sodium Atom Animation
What is the charge of each
subatomic particle?
• Proton
neutron
•+
O
• positive
none
electron
negative
Where are they found in the atom?
Neutron and
proton – in
the nucleus
Electron –
outside the
nucleus
Helium atom
animation
Chemical Element
• A pure substance that consists
on only one type of atom
Pure Substance: Iodine
Atom
• EX: every atom in a gold block looks
like all the other gold atoms
Periodic Table of the Elements
Mendeleev
Element Song(link)
“The Elements” by Tom Lehrer
•
•
•
There’s antimony, arsenic, aluminum,
•
selenium,
And hydrogen and oxygen and nitrogen
and rhenium
And nickel, neodymium, neptunium,
germanium,
And iron, americium, ruthenium,
uranium,
Europium, zirconium, lutetium, vanadium
And lanthanum and osmium and astatine
and radium
And gold, protactinium and indium and
gallium
And iodine and thorium and thulium and
thallium.
•
There’s yttrium, ytterbium, actinium,
rubidium
And boron, gadolinium, niobium, iridium
And strontium and silicon and silver and
samarium,
And bismuth, bromine, lithium, beryllium
and barium.
There’s holmium and helium and hafnium
and erbium
•
And phosphorous and francium and fluorine
and terbium
And manganese and mercury,
molybdinum, magnesium,
Dysprosium and scandium and cerium
and cesium
And lead, praseodymium, platinum,
plutonium,
Palladium, promethium, potassium,
polonium,
Tantalum, technetium, titanium, tellurium,
And cadmium and calcium and
chromium and curium.
There’s sulfur, californium and fermium,
berkelium
And also mendelevium, einsteinium and
nobelium
And argon, krypton, neon, radon, xenon,
zinc and rhodium
And chlorine, cobalt, carbon, copper,
Tungsten, tin and sodium.
These are the only ones of which the
news has come to Harvard,
And there may be many others but they
haven’t been discovered.
Symbols of Elements
• 1. First letter is capitalized
• 2. Second letter (if there is one) is
always lower case
• EXAMPLES:
• C
F
Al
• Cl
B
Mn
• Ca
H
Mg
• Cr
O
Mo
Which are symbols?
Abbreviations for elements
•C
CO
Why?
Mn
CO2
Ni
•C Mn Ni
• Only one capital letter
Trace Elements
Needed by some
organisms but only in
very small amounts
Like iodine, we need
only 0.15 mg per day
A deficiency will
cause a goiter
What are trace elements?
• Needed in the body in only small
amounts
• Like mg (milligrams)
• WHY IMPORTANT IF WE DON’T
NEED SO MUCH?
• Minerals act as catalysts (speed
up reactions) for many biological
reactions
EACH ELEMENT: All the same
atoms
• Photographic Periodic Table (link)
Which are elements?
•
•
•
•
•
•
•
•
Cu
C
CO
Co
N
NO
WHY?
Cu C N only
one kind of matter
Atomic Number
• Number of protons
of an element
Mass Number
•
•
•
•
Protons plus neutrons
Decimal number
Will round off the number
Average of masses of many atoms
Mass Number
• Mass of nucleus
What about that decimal for mass
number?
= Average of all
isotopes of
carbon
• Mass Number
What is
the
mass
number
of Na?
• Atomic Number
Atomic Number?
Mass Number?
HOW TO FIND
• Number of Protons = Atomic Number
• Number of Electrons = Number of
Protons = Atomic Number
• Number of Neutrons = Mass Number Atomic Number
How many?
• Protons
• Carbon
6
electrons
6
neutrons
6
• Chlorine
• 17
17
18
What’s a neutral atom?
• Number of protons =
number of electrons
• Example: carbon has 6 eand 6 p+
Is this a neutral atom?
=p
= e-
Same Number of electrons as
protons
• WHY?
• So the atom will be neutral (no excess
charge)
What is the mass number of…?
• Carbon
• WHY?
•
•
•
•
nitrogen
hydrogen
12
14
1
Decimal number on periodic table
Not other number in succession
Number of p + n
What is the atomic number of?
• Silicon
WHY?
fluorine
sodium
• 14
9
11
• Number in succession (not
a decimal)
• Number of protons
How do you find the number of…?
• Protons
electrons
• Atomic
Number
atomic
mass no.
number minus
(if neutral) At. No.
neutrons
YOU NEED TO KNOW
• The Names (spelled correctly)
and the Symbols (written
correctly)
• “Naturally Occurring Elements
in the Human Body”
Radioisotopes
• All elements with atomic numbers greater
than 83 are radioisotopes meaning that
these elements have unstable nuclei and
are radioactive and some under 83 have
isotope forms.
Isotope: form of an element with a
different number of neutrons
What makes atoms radioactive?
Their nuclei are unstable and
they break down at a constant
rate over time…and they have
uneven numbers of protons
and neutrons. Radioactive Decay of
Uranium
Some Radioactive Elements
Radioactive Particles Given Off
• Radioactive Decay
of Uranium
Isotopes
• Are atoms of
the same
element that
differ in the
number of
neutrons!
Number of neutrons? Isotopes?
Which is the neutral form?
Which has more uneven number
of protons and neutrons?
Number of
Protons
Positive Uses of Radioisotopes
Iodine-131
treat thyroid
cancer
Sr 89 treat
bone and
prostate
cancer
PET SCAN
Uses of Radioisotopes
• Positron Emission
Tomography
tracers
Radioactive dating
Sterillizing food and
medical equipment
Cancer
treatment
Technetium-99m
has become
the most widely
used (80%)
radioisotope for
diagnosing
diseased
organs
(especially
brain, heart,
and bone)
Which are isotopes?
•
20
F
9
16
O
8
WHY?
38
K
19
20
F
9
128
I
53
38
K
19
128
I
53
12
C
6
different # neutrons
Formula
• Abbreviation for a compound
• A COMPOUND is two or more elements
chemically bound:
Which are formulas?
Abbreviation for a compound
• H2SO4
Why?
Cl2
H20
Al
H2SO4
H20 abbreviations
for compounds (2 or more
different kinds of elements)
What is a compound?
• 2 or more different
elements
chemically joined (2+ diff.
capital letters)
• HCl
• H2SO4
H2O
NOT O2
Which are atoms?
•C N
Why?
N2
H20
• C and N only one
in number
Using The Correct Term
(get handout)
• Element
• 1 kind of Atom, Na, H
• Compound • 2 or more different kinds of
elements chemically joined, NaCl
• Abbreviation of an element, H, Cl
• Symbol
• Abbreviation of a compound
• Formula
Na2S
• 1 unit of matter H Na Cl
• Atom
• Molecule • 2 or more atoms chemically
joined H2, NaCl
Which are compounds?
• Na
N
Why?
H2
NO2 H2O
• NO2
• H 2O
• 2 or more different elements
chemically joined (2+ diff.
capital letters)
What’s the difference?
• Co
• Symbol
CO
co
formula nuttin
Which are molecules?
• Co
CO
Why?
CO2
O2
• CO
CO2 O2 two or
more atoms (alike or not
alike, it doesn’t matter)
bonded together
What are the four…
• Most abundant elements in living
matter?
C H O N
What is the relative size?
• Proton
neutron
electron
• 1 amu
•
1 amu
~1/2000
amu
• AMU=atomic mass unit= 1/12
CARBON ATOM
How do electrons arrange?
• In the outer shells?
• 2, 8, 8
• Fill inner shell first, then
go to next shell out
Get kinda complicated
beyond 2,8,8…so that’s all
we’ll do for now!
Atoms that have the same number
of electrons have the same
chemical properties.
How many electrons in each shell?
•C
O
F
Na
• 2,4
2,6
2,7
2,8,1
What are ions?
• Charged atoms
• Have lost or gained
an electron
Lost or Gained How Many e-?
• H+ Li+ Na+ K+
• Lost one e-
• Be+2 Mg+2 Ca+2
• Lost 2 e-
• Al+3
• Lost 3 e-
• F- Cl- Br- I-
• Gained one e-
•
• Gained 2 e-
S-2
Note Ions and Formulas
• Na+ Cl+1 -1
• Mg2+ Cl+2 -1
• Na+ S 2+1 -2
• Mg2+ S 2+2
-2
NaCl
1:1
MgCl2 1:2
Na2S
2:1
MgS
1:1
Which are ions?
• Cl
O-2
Why?
Na+1
N2
• O-2
Na+1
• Charged atoms (lost or gained
electrons)
• show charges as superscripts
Which electrons determine…
• The chemical
properties of the
atom?
• Outermost shell
Periodic Table Hint:
• You can tell how many
electrons are in an atom’s
outermost shell by just
looking at its position on the
periodic table!!!!!
e- in outer shells
1 2
3 4 5 6 7 8
Which atoms combine…
• with other atoms?
• Ones that do not have
filled outer electron
shells
What is the driving force to
make atoms join with other
atoms to form compounds?
• TO HAVE FILLED OUTER
ELECTRON
SHELLS!!!!!!!!!!!!!!!!!!!!!!!!
How does an atom…
• Get a filled outer
electron shell?
• Gaining, losing, or
sharing electrons
If one electron is…
• Lost what
charge will the
ion have?
•+1
If one electron is gained…
• What charge
will the ion
have?
•-1
If 2 electrons are lost…
• What charge will the ion have?
•+2
If two electrons are gained…
• What charge will the ion have?
•-2
Making Correct Formulas:
• Note how the ion charge becomes
the subscript of the other ion
•
•
•
•
Na+ ClMg2+ ClNa+ S-2
Mg2+ S-2
NaCl
MgCl2
Na2S
MgS
What do we call the forces that…
• Hold atoms
together in a
molecule?
• Chemical
bonds…not to be
confused with
James Bond
IONIC BOND
• What makes up ionic bonds?
• IONS
• WHY?
• Opposite charged ions attract
Covalent Bond
• What makes up
covalent bonds?
• Atoms that are
sharing
electrons
Comparing Bonds
IONIC BOND (gain or lose e-)
COVALENT BOND (sharing e-)
How can covalent bonds
be written?
• Single bond
•
•
C-C
C:C
double bond
C=C
C::C
triple bond
C=C
C:::C