• All ______ is made of one
or more elements.
• The atom is the smallest
particle of an element.
• A central nucleus surrounded by one or more electrons.
• The three subatomic particles are called protons,
electrons, and neutrons.
• Different atoms have different #s of subatomic particles.
Proton (p+)
• Protons have a + electric
charge.
• p+ have a mass of 1 atomic
mass unit (amu).
• p+ are found in the center core
of the atom called the nucleus.
Neutrons (n0)
• Neutrons are electrically neutral.
They have no charge.
• n0 have a mass of 1 amu.
• n0 are also located in the nucleus.
• (we hypothesize) Neutrons (n0) are
in the nucleus to keep the Protons
from repelling each other and
breaking the atom apart.
Electron (e-)
• The electron has a negative ||electric charge.
• The e- has a mass of 0.0005
amu.
(The mass of the e- is so
small compared to the p+ and n0
that it is ignored)
• The e- is found moving around
the outside of the nucleus. (ecloud)
Structure of the Helium Atom
Electron
Neutron
Proton
The periodic table gives the following
information about each element and it’s
atoms.
• Atomic Number
• Mass Number
(Atomic Mass)
• Element or
Chemical Symbol
• Chemical symbol
- an abbreviation for each
element.
- 1 or 2 letters w/ the 1st letter
being capital
• atomic # - the smaller of the 2
#s.
also the # of p+ and e-.
Finding the number of Neutrons
• The atomic mass # (or mass #)
- the sum of the # of p+ and n0.
-used to find the # of n0
n0 =mass # (rounded) - atomic #
Element
Protons
and
Electrons
Carbon
6
Oxygen
8
Neutron
Protons
Neutrons
Carbon 12
6
6
Carbon 14
6
8
Atom
Name
• ___________ called groups
or families.
• Elements in each group,
have _____ properties and
characteristics.
• Elements in horizontal rows
called _____.
Sample Periodic Table
• The periodic table
is divided into
three different
regions. The three
regions are the
metals, metalloids,
and the non –
metals which
include the noble
gases.
• Physical properties: hardness, shininess, malleability,
and ductility.
• Malleable material can be pounded into shapes.
• Ductile material can be pulled out or drawn into a long
wire.
• Metals are good conductors of heat and electricity.
• Most are also magnetic
• Noble gases (inert gases) located in family 18. They are
stable and are not reactive with other elements. Other
elements want to be like them and have their outer shell
full.
• Elements that form the zigzag line in the periodic table.
• The metalloids have some properties of a metal and
some properties of a nonmetal.
• For example, these elements have varying abilities to
conduct electricity.
Alkali Metals
• Lose 1 e- when combining with other elements
• Are highly reactive
Alkaline Earth Metals
• Lose 2 e- when combining with other elements
The Carbon Family
• has atoms that can gain, lose, or share four electrons
when reacting with other elements.
• only carbon is a nonmetal
• Molecules containing long chains of carbon atoms are
found in all living things.
• Most of the fuels that are burned to yield energy contain
carbon
The Nitrogen Family
• Contains two nonmetals,
nitrogen and phosphorus.
• Earth’s atmosphere is
almost 80 percent
nitrogen gas.
The Oxygen Family
• usually gain or share two electrons when reacting with
other elements.
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