Download The Atom

The Three Primary
Subatomic Particles...
 Protons (positive)
 Neutrons (neutral)
 Electrons (negative)

Note: protons and
neutrons are made up of
even smaller particles
called Quarks






# of protons = the atomic number
Atomic number = # of protons
# of protons determines which element it is!
Who is element # 15? Phosphorus
How many protons does lithium have? 3
What is the atomic number of tin? 50



Number of neutrons can vary, even for the
same element.
Neutrons affect the atomic mass
Isotopes



Elements can have many different isotopes



same # of protons (same element)
different # of neutrons (isotope)
Carbon-12, Carbon-13, Carbon-14,
Uranium-235, Uranium-238
Neutrons contribute to the “Strong Force”
that holds the nucleus together.


Sum of the protons
and neutrons
Electrons are not
included


Too small (1/2000)
What is the atomic
mass of this atom?




A neutral atom has
no charge.
positive charges =
negative charges.
A neutral atom has
the same # of
electrons as protons
How many electrons
does this atom have?
Atomic Mass
Protons + Neutrons
#Protons
23
11
Na
Element
Symbol
Atomic Number
# Neutrons = Atomic Mass – Atomic Number
Find the number of protons, neutrons and
electrons in the following elements
35
Cl
17
243
Am
95
35
17
Cl
243
95
Am
17 protons
17 electrons
35-17 = 18 neutrons
95 protons
95 electrons
243-95 = 148 neutrons


If an atom is not
neutral, then it has a
charge.
Ion

Charged particle
This atom has:
3 protons
(+++)
2 electrons
(- -)
 Net charge is +1 and
it is written as Li+1
 It is called a Cation



If an atom is not neutral,
then it has a charge.
Ion

Charged particle
This atom has:
9 protons (+++++++++)
10 electrons (- - - - - - - - - -)
 It is written as F-1
 It is called an Anion




How many protons?
How many neutrons?
How many electrons (if the atom is neutral?)

How many protons?
– The atomic number

How many neutrons?
– Atomic mass minus atomic number

How many electrons (if the atom is
neutral?)
– Same as # of protons






Ion: Charged Particle
Anion: Negatively Charged Particle
Cation: Positively Charged Particle
Isotope: Same # of Protons, Different #
of Neutrons.
Atomic number: # of Protons
Atomic mass: Protons + Neutrons

Just like members of
a family, certain
elements of the
periodic table share
similarities. Like
good looks!



Families of elements are groups of elements
that have similar properties.
Groups can be a single column or a whole
section of the periodic table.
Let’s start with the big groups first.



Similar metals are
grouped together.
Two groups of metals
are located on the left
side of your periodic
table.
Some are located on
the right side of the
table left of the stair
steps. Most are
located in the middle
of the periodic table.

The elements
that are
usually poor
conductors of
heat and
electricity.


First notice the
location of
nonmetals.
Second notice what
these elements are.



The elements that are
intermediate conductors of heat
and electricity. (can do it but only
under certain conditions)
Sometimes called Metalloids
Found by the “stair-step” divider
between metals and non-metals


Specific groups that have similar properties are
in the columns on the periodic table.
These are the numbers 1-18 or 1A -8A across
the top of the table.




sodium and potassium
Brainiac
The highly reactive
metallic elements
located in Group 1
of the periodic
table.
Tend to lose 1
electron
They are Cations
(+1 charge)
React with water

Alkali Metals
are located on
the left edge of
the periodic
table
Lumps of Calcium




The reactive metallic
elements located in
Group 2 of the
periodic table.
Tend to lose 2
electrons
They are Cations
(+2 charge)
Do not react with
water.

The alkaline-earth
metals make up
the second column
of elements from
the left edge of the
periodic table.


These are metallic elements in Group 3-12 of
your periodic table.
They are “transition metals” because they shift
from being similar to group 2 (alkali metals)
over to being like group 13 moving left to right.
Halogen
Lamps




Bromine
burning
The highly reactive elements located in
Group 17 of the Periodic table.
Are all diatomic(F2, Cl2, Br2, I2)
Atoms Tend to gain 1 electron
They are Anions (-1 charge)

The halogens
are in the
second column
from the right
of the periodic
table.


No not kings and queens.
The unreactive gaseous elements located
on Group 18 of the periodic table.


Noble gases are
located on right
edge of the
periodic table.
And on the throne
when kings and
queens fart !




Diatomic = two atoms
There are 7 diatomic atoms
N2, O2, F2, Cl2, Br2, I2, H2
Remember them by the rule of “7”




Starts with element 7 = Nitrogen
Forms a 7 through oxygen and down to iodine
The 7th diatomic element is hydrogen
Man-Made Elements
• Which are the man-made
or synthetic Elements?
• How are synthetic elements made?

Cyclotron, protons, alpha particles
and heavy atoms
• Why do scientists continue to
try to make elements?