Download Document

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

History of molecular theory wikipedia, lookup

Unbinilium wikipedia, lookup

Ununennium wikipedia, lookup

Extended periodic table wikipedia, lookup

Tennessine wikipedia, lookup

Periodic table wikipedia, lookup

Chemical element wikipedia, lookup

Dubnium wikipedia, lookup

Oganesson wikipedia, lookup

Valley of stability wikipedia, lookup

Transcript
The Atom
I- Theories About the Atom:
A- The term Atom comes from
the Greek word meaning
“invisible” or “that which
cannot be further cut”. This
comes for the Greek thinker
Democritus more than 2000
year ago.
1-The Greeks believed that all
matter was made up four basic
elements
Fire
Air
Earth
Water
B-Dalton’s Model: in the early
1800’ John Dalton said the
atom was a solid particle that
could not be divided, and
each element had its own
kind of atom.
C-Thomson’s Model: in 1897
J.J. Thomson discovered that
the atom was made up of
smaller particle. Thomson
discovered the electron.
1- The atom was known to be
neutral. The atom must also
have a positive charged
particle.
a- Thomson never discovered the
positive particle but he knew it
existed.
b- His model known as
“Plum Pudding”
D-Rutherford’s Model: In
1908, Ernest Rutherford fired
a stream of tiny positively
charged particle at a very thin
sheet of gold foil. He
discovered the Nucleus of the
atom and found that it
contained what Thomson was
looking for the positively
charged particle the Proton.
1-Ruther Model is known as
“The Solar system”.
E-Bohr Model: In 1913 Niel
Bohr said that the electrons
move in a definite orbit
around the nucleus known
as.
1-Energy Level: is the path an
electron takes around the
nucleus of the atom, it related
to the amount of energy it has.
2-Electrons Energies: By heating
up or passing electricity
through the atom you can
increase its energy.
a-If the atom gains enough energy
the electron can jump to a
higher energy level called an
Excited State.
b- To return to it’s original state
the atom releases the extra
energy in the form of a PHOTON.
c-Spectrum is the finger print of an
element each element has its own
spectrum.
F-Chadwick’s Model: In 1932
Chadwick discovered a
particle in the nucleus of the
atom. The Neutron has NO
CHARGE but has more mass
than the proton. This
completed the model of the
atom.
Electron
Neutron
Proton
1-Today: the atom is described
as a central mass surrounded
by an electron cloud.
II- How Atoms Differ
A- All atoms of an element
have the same number of
protons. The number of
protons determines what
the element is.
1- Atomic Number is the
number of protons of an
atom.
2- Mass Number: is the total
number of Protons and
Neutrons in an atom.
a- To find the number of neutrons
in an atom all you do is
subtract the atomic number
from the mass number.
Mass Number
B-Isotopes: Atoms of the same
element with the same atomic
number but a different number
of neutrons.
III-Classifying Elements:
A-The Periodic Table: Was
created by Mendeleev, he
put the elements with the
same characteristics into
columns.
1-The elements line up in
increasing atomic
numbers.
B- Arrangement of Table:
1-Each row is called a
period and each column
is called a group.
2-If you know something
about an element in a
group you know
something about them
all.
3-Each box has an
element’s symbol, name,
atomic number, mass
number, and the number
of electrons in each
energy level.
Atomic Number
Symbol
Name
13
2
Al
8
3
Aluminum
26.98
Number
of
electrons
in each
energy
level
Average atomic mass