Download Atoms and Elements: Are they Related?

Atoms and Elements: Are they
Related?
Fall 2011
ATOMS
• ALL MATTER IS MADE OF ATOMS
• Definition: ATOMS ARE THE
SMALLEST PIECE OF MATTER and
CANNOT BE BROKEN DOWN INTO
A SIMPLER SUBSTANCE.
ATOMS HAVE 3 BASIC PARTS
(Subatomic Particles)
• PROTONS
• NEUTRONS
• ELECTRONS
– PROTONS (POSITIVE CHARGE)
– ARE FOUND IN THE NUCLEUS AND
MAKE UP MOST OF THE MASS OF
THE ATOM.
– VERY IMPORTANT!!! The number of
protons an atom has tells you what
kind of atom it is!!!!
The Atomic Number is the
number of Protons
Pg. 158
–NEUTRONS (NO CHARGE)
• ARE FOUND IN THE NUCLEUS
• MAKE UP PART OF THE MASS
OF THE ATOM
Finding the Number of
Neutrons for an Atom
• The protons and neutrons make up the
mass of an atom.
• If you know the protons (atomic
number) then you can find the number
of neutrons by subtracting the atomic
mass from the # of protons (atomic
number).
atomic mass - # of protons = # of neutrons
Isotopes
• Atoms of the same element that have
a different number of neutrons.
EX: Carbon
Carbon-12
Carbon-13
Carbon-14
Isotopes & Radioactive
Decay
• Atoms are most stable when they have the same
number of Pro/Neu in the nucleus…
• So, having more neutrons causes atom to be
unstable & “repulsion” builds up.
• Nucleus becomes more stable when the extra
particles are released & energy is given off.
• RD is the release of extra nuclear
particles & energy.
– ELECTRONS (NEGATIVE CHARGE - )
•FOUND IN THE ELECTRON SHELL
(cloud) ORBITING THE NUCLEUS.
•TAKES UP MOST OF THE SPACE IN
AN ATOM.
•The # of electrons = the # of protons
Valence Electrons
• Outermost electron(s) in the
cloud/shell
• 8 is the magic number!!!!!! (octet
rule)
Ions
• Atom where the total number of
electrons does not equal the total
number of protons (atom will have a
pos or neg charge)
– Cation= pos (loss of e-)
– Anion=neg (gain of e-)
– EX: Fe2+, Al3+, O2-
Label the atom below on your
packet!
What type of
atom is this?
How do you
know?
Let’s Break for Questions???
• How many protons should Hydrogen
have?
• How about Oxygen?
• Which particles are located in the
nucleus of an atom?
• Where are the electrons located?
Atomic Size
-A typical atom is about one ten-billionth of
a meter in diameter. (THAT’S REALLY,
REALLY SMALL AND WHY WE CAN’T SEE
THEM WITH A REGULAR MICROSCOPE)
-ATOMIC MASS = Protons + Neutrons.
-Most of the atomic mass comes from the
nucleus.
-Electrons weigh very little. That is why
they do not add to the mass of the atom.
-They DO contribute to the SIZE.
Isotopes & Mass Number
• So if protons and neutrons contribute
to mass, if we have a different
number of neutrons, will the mass be
affected?
• EX: since C-14 has 8 neutrons, the
mass number is 14amu instead of
12amu (C-12).
Discovery of the Atom (pg. 80)
By the early 1800’s, John Dalton proposed
that all substances are made up of atoms.
In 1898, J.J. Thomson, proposed that
atoms are made up of smaller parts.
In 1911, Ernest Rutherford,
proposed that atoms have
electrons and a positively charged
nucleus.
Dalton’s Atomic Theory
1) All matter is made of atoms. Atoms are
indivisible and indestructible.
2) All atoms of a given element are
identical in mass and properties
3) Compounds are formed by a
combination of two or more different
kinds of atoms.
4) A chemical reaction is a rearrangement
of atoms.
Niels Bohr’s model of the atom
• Electrons revolved around the
nucleus in circular paths called
orbits.
Current Atomic Theory:
Electron Cloud Model
Electrons travel in regions
of various thicknesses
called clouds.
• ELEMENTS
• DEFINITION: PURE SUBSTANCES MADE OF
ONLY 1 KIND OF ATOM.
• ARE THE BUILDING BLOCKS OF MATTER.
• CANNOT BE BROKEN DOWN INTO A SIMPLER
SUBSTANCE.
• HAVE THEIR OWN UNIQUE SET OF
PROPERTIES THAT NO OTHER ELEMENT HAS.
ELEMENTS
• There are 92 naturally occurring
elements on the periodic table. This
means they are in nature and not
made in a laboratory by scientists.
• As of this year (2011) there are 118
confirmed elements. There are 4
more under investigation and
scientific testing.
Let’s Stop for Questions!
• What type of atoms make up the
element Lithium? Carbon? Sodium?
• ELEMENTS ARE MADE OF ONLY 1 KIND OF
ATOM.
• SOME COMMON ELEMENTS
– HYDROGEN (H), HELIUM (He), OXYGEN
(0),
– Notice that the first letter is capital and
the next letter is lower case.
Atoms and Elements Activity
• As a group, look at the food labels on
the items at your table. Make a list of
the items in the left hand side column
and in the right hand side column
make a list of any elements found in
that substance.
• You may use your periodic table to
help you identify the elements.
The food item
would be:
Cooked Ham
What are the
elements that
are found on
this food label?
QUESTIONS????
• What are the most commonly occurring
elements in the food labels?
• What items seemed to have the most
amount of elements in them?
• Can you predict what that means about
the food item?
• Why do you think the baby formula has
such a variety of elements?
• Can you predict what the other items on
the food label are if they are not
elements?
Wrap Up
Use your dry erase boards to write answers
and hold them high!!!
• Protons have what charge?
• Electrons have what charge?
• Which parts of an atom make up the
mass of the atom?
• Elements are made up of?
• The element lead is made up of what
kind of atoms?
Periodic Table
• The periodic table is an organized
table of each element.
• Each box gives information about
each type of element found on Earth.
Dmitri Mendeleev (1869)
In 1869 Mendeleev and Lothar Meyer (Germany)
published nearly identical classification schemes
for elements known to date. The periodic table is
base on the similarity of properties and reactivities
exhibited by certain elements. Later, Henri
Moseley ( England,1887-1915) established that
each elements has a unique atomic number, which
is how the current periodic table is organized.
http://www.chem.msu.su/eng/misc/mendeleev/welcome.html
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3.3 Periodic Table
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• ELEMENTS ARE ORGANIZED IN THE
PERIODIC TABLE ACCORDING TO ATOMIC
NUMBER.
• ELEMENTS ARE ORGANIZED IN THE PERIODIC
TABLE OF ELEMENTS ACCORDING TO THEIR
SIMILAR CHARACTERISTICS
• 3 major groups: metals, nonmetals and
metalloids
• See pg. 57 in book
Element Info in Each Box
Atomic weight
Atomic Number
Symbol
Name
Information from the periodic table
Atomic Number- Number of
Protons in an atom
Silver = 47 protons
Iron- Fe (Ferrum)
Lead- Pb (Plumbum)
Elements & their symbols
SOME COMMON ELEMENTS
HYDROGEN (H), HELIUM (He), OXYGEN (0),
Notice that the first letter is capital and the
next letter is lower case.
Gold- Au (Aurum)
Arrangement of the Periodic table
Periods – Rows are called periods. The
elements in these rows change
conductivity and number of electrons as
you move across the table.
Groups – Columns are called groups or
families. These elements have the same
properties because of the number of
electrons.
How is the Periodic Table Organized?
Periods
Even though they
skip some squares
in between, all of
the rows go left
to right. When
you look at a
periodic table,
each of the rows
is considered to
be a different
period
Across the Periodic Table
Periods: Are arranged horizontally across the
periodic table (rows 1-7)
These elements have the same number of valence shells.
1
IA
1
2
IIA
13
IIIA
14
IVA
15
VA
18
VIIIA
16
VIA
17
VIIA
2nd Period
2
3
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
4
5
6th Period
6
7
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3.3 Periodic Table
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Groups
When a column
goes from top to
bottom, it's
called a group or
family.
Groups are often called families
because these elements seem to
be related.
**Elements in the same group show
similarities in their chemical and
physical properties.
Down the Periodic Table
Family: Are arranged vertically down the periodic table
(columns or group, 1- 18 or 1-8 A,B)
These elements have the same number electrons in the outer most
shells, the valence shell.
1
IA
1
18
VIIIA
Alkali Family:
1 e- in the valence shell
2
IIA
13
IIIA
14
IVA
15
VA
16
VIA
17
VIIA
2
3
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
4
Halogen Family:
7 e- in the valence shell
5
6
7
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Reading the Periodic Table: Classification
Nonmetals, Metals, Metalloids, Noble gases
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Infamous Families of the Periodic Table
Notable families of the Periodic Table and some important members:
Halogen
Alkali
Noble Gas
Alkaline
Chalcogens
1
18
(earth)
IA
VIIIA
1
2
IIA
13
IIIA
Transition Metals
14
IVA
15
VA
16
VIA
17
VIIA
2
3
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
4
5
6
7
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3.3 Periodic Table
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Alkali Group
-Group #1
-1 valence electron in outer shell
-very reactive with water & other elements
-low densities & melting points
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Alkaline Earth Group
-Group #2
-2 valence electrons in outer shell
-very reactive but not as much as alkali
-denser, harder & higher melting points
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Transition Metals
-Groups 3-12
-Valence electrons vary
-Usually found combined with other elements
-higher melting points, good conductors
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Halogen Group
-Group #17
-7 valence electrons in outer shell
-most combined to make salts (salt formers)
-most are non-metals
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Noble Gas Group
-Group # 18
-8 valence electrons in outer shell (the happy
gases! )
-NOT REACTIVE
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Periodic Table: Metallic arrangement
Layout of the Periodic Table: Metals vs. nonmetals
1
IA
1
18
VIIIA
2
IIA
13
IIIA
14
IVA
15
VA
16
VIA
17
VIIA
2
3
4
5
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
Metals
11
IB
12
IIB
Nonmetals
6
7
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Summary
Periodic Table: Map of the Building block of matter
Type: Metal, metalloid and Nonmetal
Groupings: Representative or main, transition and
Lanthanide/Actanides
Family: Elements in the same column have similar
chemical property because of similar valence
electrons
Alkali, Alkaline, halogens, noble gases
Period: Elements in the same row have valence
electrons in the same shell.
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The Periodic Table Of Elements
Elements are classified:
*Metals
*Nonmetals
*Metalloids
Xenon
Scandium
Properties of a metal
Good conductors – conducts heat or
electricity
*Malleable - flattened
*Ductile – can be made into wires
*Shiny- you can see you reflection
*
Gold
Iron
Magnesium
Properties of a Nonmetal
*Not malleable – cannot be
flattened
*Not shiny
*Poor conductors
Chlorine
Helium
Bromine
Properties of Metalloids
•Semiconductors – Average conductors
•Shiny but brittle
Silicon
Arsenic
Boron
Sulfur
GOLD (AU)
Silver
ELEMENTS IN OUR BODIES
IODINE
•
•
•
•
•
•
•
•
•
•
•
1.Oxygen (65%)
99% of the mass of the human body is made
up of only six elements: oxygen, carbon,
2.Carbon (18%)
hydrogen, nitrogen, calcium, and phosphorus.
3.Hydrogen (10%) Every organic molecule contains carbon. Since
65-90% of each body cell consists of water (by
4.Nitrogen (3%)
weight), it isn't surprising that oxygen and
5.Calcium (1.5%)
hydrogen are major components of the body
6.Phosphorus (1.0%)
7.Potassium (0.35%)
8.Sulfur (0.25%)
9.Sodium (0.15%)
10.Magnesium (0.05%)
11.Copper, Zinc, Selenium, Molybdenum,
Fluorine, Chlorine, Iodine, Manganese, Cobalt,
Iron (0.70%)
• 12.Lithium, Strontium, Aluminum, Silicon, Lead,
Vanadium, Arsenic, Bromine (trace amounts)
Elements in the body
Oxygen
Carbon
Hydrogen
Nitrogen
Calcium
Phosphorus
Potassium
Sodium
Chlorine
Magnesium
Sulfur
GASES
FLUORINE
KRYPTON
NITROGEN
NEON
Atoms to Elements to ???
• ELEMENTS & COMPOUNDS ARE
THE BASIC BUILDING BLOCKS OF
MATTER
• EACH ELEMENT & COMPOUND
HAS SPECIFIC PROPERTIES
COMPOUNDS ARE MADE OF 2 OR
MORE DIFFERENT KINDS OF
ATOMS/Elements BONDED
TOGETHER
COMPOUNDS ARE MADE OF 2 OR
MORE DIFFERENT KINDS OF ATOMS
BONDED TOGETHER
Compounds
http://web.neo.edu/rjones/Pages/1014new/Lecture/chemistry/chapter_9/pages/chemica
l_bonds.html
• COMPOUNDS ARE MADE OF 2 OR MORE
DIFFERENT KINDS OF ATOMS BONDED
TOGETHER
• FOR A COMPOUND TO FORM, A CHEMICAL
CHANGE MUST TAKE PLACE (A REACTION)
• THE ELEMENTS THAT COMBINE MAKE A NEW
SUBSTANCE WITH NEW PHYSICAL PROPERTIES
• COMPOUNDS CANNOT BE BROKEN DOWN
PHYSICALLY. REQUIRES A CHEMICAL CHANGE
• MORE COMMON THAN ELEMENTS
NaCl
+
=
TABLE SALT
• COMPOUNDS ARE IDENTIFIED BY A
CHEMICAL FORMULA
• THE ELEMENTS THAT COMBINE TO
MAKE THE COMPOUND CHANGE
PROPERTIES
NaCl
+
=
TABLE SALT
Atomic Structure & Chemical
Bonds
• Octet rule= when atoms of elements
react, they ten to lose, gain or share
electrons to achieve the same
electron arrangement as the noble
gases.
3 Ways Elements Bond
• Ionic= loss or gain of electron (metal +
non-metal)
• Metallic= metal atoms share pooled
electrons
– (pooling=electrons gathered together)
• Covalent=sharing of electrons (nonmetal elements)
Ionic
Covalent
• Carbon forms lots of covalent bonds
Metallic
• A way of writing
how many atoms
are in a compound.
Chemical Formulas
Written as: C4H10
Butane
Written as: CH4
Methane
= how many total molecules
Subscripts= how many
atoms
•
•
•
•
FeO2
H2O
C6H12O6
2Li + 2O2
Chemical Changes Through Chemical Reactions
A chemical reaction – Process in which the
physical and chemical properties of the original
substance(s) CHANGE as new substances with
different properties are formed.
A burning match is
a good example of
a chemical
reaction.
Application of a spark to
the chemicals on the
match head start the
chemical reaction.
Signs of a chemical change – heat given off,
light given off, new substance formed – black
material on the match head when the fire is
extinguished.
Parts of a Chemical Reaction
Reactants – Substances that begins the
chemical reaction (chemicals on match
head)
Products – Substances produced in the
reaction (black material on match)
In other words:
REACTANTS CHANGE INTO PRODUCTS
CHEMICAL EQUATIONS
• Chemical equations are symbols used to
describe the details of a chemical reaction.
• Shows how the reactants changed into the
product.
• This involves indicating all the atoms
involved in the reaction.
Fe + O2
Reactants:
Iron and oxygen
Plus Sign:
Shows substances
combine
FeO2
Arrow:
Means “yields”
takes the place
of an = sign
Product:
Ferrous oxide
(rust)
Law of Conservation of Matter
Matter cannot be created or destroyed, it
just changes forms.
The total mass of the reactants must
equal the total mass of the product.
Law of Conservation of Mass
Alka-Seltzer and Water
http://www.skyweb.net/science/balancing_chemical_equations_examples.htm
Balancing Equations
• The number of atoms of the reactants
must equal the number of atoms in
the product. (Law of Conservation of
Matter)
Ex: 2Na + Cl2 -> 2NaCl
4P + 5O2 -> P4O10
Balancing Equations
• Rules
– Make sure that all atoms are equal on
both sides.
– You can only add coefficients.
• Changing the subscripts will change the
identity of the compound.
– H2O & H2O2
EX: 2Na + Cl2 -> 2NaCl
H2 + O2 -> 2H2O
(Not balanced… So…)
2H2 + O2 -> 2H2O
Balancing Chemical Equations
Hg + O2
HgO
H2 + Cl
HCl
Mg + O2
MgO
O2 + H 2
H 2O
CH4 + O2
CO2 + H2O
Fe + Cl2
FeCl3
Hg +
O2
HgO
H2 + Cl
HCl
Mg + O2
MgO
O2 +
H2
H2O
Fe + Cl2
FeCl3
CH4 +
O2
CO2 +
H2O
• CAN YOU TELL WHICH IS A MOLECULE
OF AN ELEMENT OR A COMPOUND?
WHICH SHOWS AN ATOM?
• MOLECULES ARE 2 OR MORE ATOMS
ATTACHED TOGETHER
– THEY CAN BE THE SAME KIND
(ELEMENTS)
– THEY CAN BE DIFFERENT KINDS
(COMPOUNDS)
Examples: H2O, NaCl.
Periodic Table: electron behavior
The periodic table can be classified by the behavior of their electrons
West (South)
METALS
Alkali
Alkaline
Transition
These elements
tend to give up
e - and form
CATIONS
1
IA
1
Mid-plains
METALLOID
These elements
will give up e- or
accept e-
East (North)
NON-METALS
Noble gas
Halogens
Calcogens
These elements
tend to accept
e - and form
ANIONS
2
IIA
13
IIIA
14
IVA
18
VIIIA
15
VA
16
VIA
17
VIIA
2
3
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
4
5
6
7
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