Download elements_and_the_periodic_table_2011

Aristotle and Plato
believed there were
four elements: Earth, Fire, Air
and Water. Their ideas stayed
for 2000 year because of their
position as philosophers.
 The elements,
working alone or
in combinations,
make up the entire
universe in fact
everything around
us.
Elements are the simplest
type of pure substance.
Atoms are the smallest part
of an element that has all the
properties of an element.
Gold Element
Gold Atom
Thompson model Rutherfor Model
Bohr Model
Wave Model
Indivisible Divisible
Democritus
Aristotle &
Plato
Dalton
Thomson
Rutherford
Bohr
Wave
Electron
Nucleus Orbit
Electron
Cloud
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Atoms are composed of three types of
particles:
• Protons: Positively charged particles
that are found in the nucleus
• Neutron: Uncharged (Neutral)
particles that are found in the nucleus
• Electrons: negatively charge particles
found moving around the nucleus.
Neutrons
Protons
Electrons
 A space in which electrons are
likely to be found.
 Electrons whirl about the
nucleus billions of times in
one second
 They are not moving around
in random patterns.
 Location of electrons depends
upon how much energy the
electron has.
 Depending on their energy they are
locked into a certain area in the
cloud.
 Electrons with the lowest energy
are found in the energy level
closest to the nucleus
 Electrons with the highest energy
are found in the outermost energy
levels, farther from the nucleus.
The nucleus is the core or
center of the atom.
99% of the mass.
Used to measure the subatomic
particles.
Protons are 1 amu
Neutrons are about 1 amu
-27
1 amu = 3.6609 x 10 pounds
Electron mass = 0.0005446623 amu
Proton mass = 1.00727638 amu
Neutron mass = 1.0086649156 amu
Region they were found:
Magnesium was found in the Greek region
Magnesia
Greek or Latin word:
Lithium came from the Greek word lithos
Named for a Scientist, Founder or Country:
Einsteinium was named after Albert Einstein.
Fermium was named after Enrico Fermi
Polonium was named for Poland
Each element has a unique symbol
First Letter of name (first letter always
capitalized):
Hydrogen (H)
Sulfur (S)
Iodine (I)
If the first letter was already used or is very
common, add another letter from the name
(second letter is always lower case):
Aluminum (Al), Platinum (Pt),
Cadmium (Cd)
Some symbols come from their Greek or
Latin name:
Mercury (Hg) comes from Greek
• Elements are defined by the # of
protons located inside the atom
• Atomic number is the number
of protons located in the
nucleus.
• Atomic Number identifies the
element and never changes.
 All Nitrogen (N) atoms have 7 protons
 All Carbon (C) atoms have 6 protons
 All Oxygen (O) atoms have 8 protons
 Atomic mass is the average mass of
all existing isotopes of that
element. This is why it is usually
not a whole number.
 An isotope is an atom that has the same
number of protons (atomic number) as
another atom but a different number of
neutrons.
Example:
 C has Isotopes of 12, 13 and 14
 All Carbons have 6 protons, but
number of neutrons varies.
All atoms have a mass number.
Mass number is the sum of the protons
and neutrons in its nucleus.
 A molecule is the combination of
atoms formed by a covalent bond.
(using electrons)
 A Compound is a substance made up of
molecules that contain more than one
kind of atom; two or more elements
chemically combined.