Transcript Atoms and Elements: Are they Related?

Atoms and Elements and Compounds:
Are they Related?
BGJHS Science
7th Grade
Matter
• Matter is anything that has mass and
volume (takes up space).
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!!!!
–NEUTRONS (NO CHARGE)
• ARE FOUND IN THE NUCLEUS
• MAKE UP PART OF THE MASS
OF THE ATOM
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.
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-
How to Find:
• # of Protons
– The atomic number IS the number of
protons
– Atomic number is located on the
periodic table
# of Protons
• If the atomic # is 7, what is the # of
protons?
• If the atomic # is 15, what is the # of
protons?
• If an atom has 22 protons, what is its
atomic #.
• How many protons does Oxygen have?
What is Oxygen’s atomic #?
• Neon has 10 protons. What is its atomic #?
• If an atom has 35 protons, what is the
name of the atom?
How to Find:
• # of Neutrons
– You can find the number of neutrons by
subtracting the atomic mass from the # of
protons (atomic number).
atomic mass - # of protons = # of neutrons
# of Neutrons
• If an atom’s mass is 9amu and has 4
protons, how many neutrons does it
have?
• If an atom’s mass is 14amu and has
atomic number of 7, how many neutrons
does it have?
• How many neutrons does aluminum
have?
• How many neutrons does calcium have?
• An atom has a mass of 28amu and 14
neutrons, what type of atom is it?
# of Neutrons
• If an atom of germanium has 41
neutrons and 32 protons, what is its
atomic mass?
• Nickel has an atomic number of 28
and has 31 neutrons, what is its
mass?
Isotopes & Mass Number
• 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).
Isotopes
• Atoms of the same element that have
a different number of neutrons.
EX: Carbon
Carbon-12
Carbon-13
Carbon-14
How to Find
• # of Electrons
–The # of electrons IS EQUAL to the
# of protons
# of Electrons
• If Helium has 2 protons, how many
electrons does it have?
• If the atomic number of magnesium is
12, how many electrons does it have?
• If an atom has 21 electrons, what type
of atom is it?
How to Find:
• Atomic Mass
– You can find the atomic mass by adding the # of
protons and the # of neutrons
– # of protons + # of neutrons = atomic mass
Putting it all together…
Element Atomic # Atomic
Mass
Au
Cr
B
Proton
79
Neutron Electron
118
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11
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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
that shows the electrons
revolving around the nucleus in
circular paths called orbits.
Current Atomic Theory:
Electron Cloud Model
Electrons travel in regions
of various thicknesses
called clouds (shells).
Label the atom below on your
packet!
What type of
atom is this?
How do you
know?
PIN THE NUCLEUS ON THE
ATOM
Elemental Candy
• ELEMENTS ARE PURE SUBSTANCES MADE OF
TWO OR MORE OF THE SAME 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.
• ELEMENTS
• 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 the year 2015 there are 118
known elements but there are gaps.
Elements
• Most Elements
– are rarely found alone in nature
– react with water or oxygen
– easily undergo a chemical change
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?
PERIODIC PATTERNS
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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• ELEMENTS ARE ORGANIZED IN THE
PERIODIC TABLE ACCORDING TO
INCREASING ATOMIC NUMBER.
• ELEMENTS ARE ORGANIZED IN THE PERIODIC
TABLE OF ELEMENTS ACCORDING TO THEIR
SIMILAR CHARACTERISTICS
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)
Element Info in Each Box
Atomic Mass
Atomic Number
Symbol
Name
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
• There are 7 periods. Each period
represents the number of electron
shells.
– Elements in period 1 have 1 electron
shell.
– Elements in period 5 will have 5 electron
shells.
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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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.
There are 8 main groups across the
periodic table. Groups or families have the
same number of electrons in the outermost
shell. The group number tells you how many
electrons are in the outermost shell.
Group 1 has 1 electron in outermost
shell.
Group 4 will have 4 electrons in
outermost shell.
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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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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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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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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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
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
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
Metals
10
11
IB
12
IIB
Nonmetals
Sulfur
GOLD (AU)
Silver
ELEMENTS IN OUR BODIES
IODINE
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•
•
•
•
•
•
•
•
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