ELEMENTS AND ATOMS NOTES
Matter and Atoms




Matter is anything that
takes up space and has
mass
There are 4 phases of
matter solid, liquid, gas,
and plasma.
All matter is made of
atoms.
Atoms are the building
blocks of matter, sort of
how bricks are the
building blocks of houses.
The Atomic Model





An atom has three parts.
Protons are positive and in
the nucleus of the atom.
Neutrons have a neutral
charge and are also
found in the nucleus.
Electrons have a negative
charge and they orbit the
atom in what is known as
an electron cloud.
Brain Pop Atoms Movie
John Dalton-The Atomic Man



John Dalton was an
English chemist.
He came up with the
many of the ideas that
we still utilize today
about atoms and the
way they are
represented.
Through his research
Dalton developed 5
postulates or things he
believed about atoms.
Dalton’s Postulates
1.
2.
3.
4.
5.
Every element is composed of
tiny particles.
These particles are called
atoms.
All atoms of a given element
are identical, atoms of
different elements have
different properties.
Atoms of an element are NOT
changed into atoms of another
element through chemical
processes. Matter can not be
created nor destroyed.
Compounds are formed when
atoms of more than one
element combine.
Dalton’s Laws


Law of Constant
Composition is that “any
given compound always
consists of the same
atoms and the same
ratio of atoms.
For example, water
always consists of
oxygen and hydrogen
atoms, and it is always
89% oxygen by mass
and 11% hydrogen by
mass.
Dalton’s Laws



Law of Conservation of
Mass is that the total mass
of materials before and
after a chemical reaction
must be the same.
Matter can not be created
or destroyed during a
chemical reaction.
The mass of the reactants
should be equal to the
mass of the products.
Elements






Elements are the alphabet to the
language of molecules.
To make molecules, you must
have elements.
Elements are made of atoms.
While the atoms may have
different weights and
organization they are all built the
same way.
Elements can not be broken down
into smaller substances by
chemical or physical means.
Elements contain one type of
atom(s).
Element Song
Naming the Elements







The first 103 elements have
internationally accepted
names, which are derived
from:
The compound or substance in
which the element was
discovered.
An unusual or identifying
property of the element.
Places, cities, and countries.
Famous scientists.
Greek Mythology
Astronomical objects.
Different types and versions of atoms
More Information about Elements



Elements are the
building blocks of all
matter.
The periodic table is a
list of all of the elements
that can build matter. It’s
a little like the alphabet
of chemistry.
The periodic table tells
us several things…
Periodic Table Basics
Atomic Number:
Number of protons and it is also
the number of electrons in an atom
of an element.
Element’s Symbol:
An abbreviation for the
element.
Elements Name
Atomic Mass/Weight:
Number of protons + neutrons.
8
O
Oxygen
16
Atomic Number tells how many protons
 For every proton (+) there is an electron (-)
 Atomic mass number tells haw many P and N
number tells haw many P and N

Atomic Mass= (#P) + (#N)
Practice

Open your books to
page L*169 and use
the periodic table for
the practice elements.
Fluorine

Symbol=

Atomic #=

Atomic Mass=

# P=

#E=

#N=
Practice
Boron
Zinc
• Symbol=
• Symbol=
• Atomic #=
• Atomic #=
• Atomic Mass=
• Atomic Mass=
• # P=
• # P=
• #E=
• #E=
• #N=
• #N=
Structure of an Atom





Nucleus (protons and
neutrons)
1st shell =2 electrons
2nd shell =8 electrons
3rd shell =8 electrons
4th shell =18 electrons
Electron Rules




You can’t just shove all
of the electrons into the
first orbit of an electron.
Electrons live in
something called shells.
Only so many can be in
any certain shell.
The electrons in the
outer most shell of any
element are called
valence electrons
Different Atomic Models


There are two models
of the atoms we will
be using in class.
Bohr Model and the
Lewis Dot Structure
The Bohr Model



The Bohr Model shows
all of the particles in the
atom.
In the center is circles.
Each circle represents a
single neutron or proton.
Protons should have a
plus or P written on
them. Neutrons should
be blank or have an N.
In a circle around the
nucleus are the electrons.
Electrons should have a
minus sign or an e.
Let’s Draw LITHIUM!!!!!!!





How to draw a Lithium
atom
First, look at the Periodic
Table
Second, determine the
number of protons (Look
@ the atomic number)
Then determine the
number of neutrons
(Atomic mass – atomic
number)
Then determine the
number of electrons (Look
@ the atomic number)
3
Li
Lithium
7
The Lewis Dot Structure for Oxygen


The Lewis Dot Structure
is a bit different from
the Bohr model.
It only shows the
element symbol and
it’s outer most electron
shell.
-
-
-
+
+ + +
-
-
+ + +
+
-
-
•
• O ••
••
-
Lewis Dot Structure for Lithium
1.
2.
3.
Write the symbol.
Start on the right
hand side, working
your way clockwise
around the symbol.
Try Lithium
Practice
Magnesium
• Symbol=
• Atomic #=
• Atomic Mass=
• # P=
• #E=
• #N=
Now Draw the Atom in
both Bohr and Lewis Dot
Structure: