Download Elements and the Periodic Table

MATTER,
ELEMENTS, &
ATOMIC
STRUCTURE
MATTER
• Matter is anything that has
mass and takes up space.
• Ex: buildings, a fork, air, your
clothes, etc…
• .
ELEMENTS
• Elements are the simplest pure
substances, and they cannot be
broken down into any other
substances.
• Elements are often called the
building blocks of matter because all
matter is composed of one element
or a combination of two or more
elements.
WHAT IS AN ATOM?
• An atom is the smallest
particle of an element
(or unit of matter) that
retains the identity of
the substance.
ATOMIC STRUCTURE
• ATOMS ARE COMPOSED OF 2 REGIONS:
• NUCLEUS: THE CENTER OF
THE ATOM THAT CONTAINS
THE MASS OF THE ATOM
• ELECTRON CLOUD: REGION
THAT SURROUNDS THE
NUCLEUS THAT
CONTAINS MOST
• OF THE SPACE IN
• THE ATOM
Nucleus
Electron
Cloud
ELECTRON CLOUD
EACH ATOMIC SHELL CAN HOLD A CERTAIN NUMBER OF ELECTRONS
BEFORE IT IS FULL. ONCE THAT SHELL IS FULL, THE ELECTRONS
WILL FILL THE NEXT SHELL.
WHAT’S IN THE NUCLEUS?
The nucleus contains 2 of the 3 subatomic
particles:
Bohr Model
• Protons (p+) : positively
charged subatomic
particles
• Neutrons (n0): neutrally
charged subatomic
particles
WHAT’S IN THE ELECTRON
CLOUD?
• The 3rd subatomic particle
resides outside of the
nucleus in the electron
cloud.
• Electron (e-): the
subatomic particle with a
negative charge and
relatively no mass
HOW DO THESE PARTICLES
INTERACT?
• PROTONS AND NEUTRONS LIVE COMPACTED IN THE
TINY, POSITIVELY CHARGED NUCLEUS ACCOUNTING
FOR MOST OF THE MASS OF THE ATOM.
• THE NEGATIVELY CHARGED ELECTRONS ARE SMALL
AND HAVE A RELATIVELY SMALL MASS BUT OCCUPY A
LARGE VOLUME OF SPACE OUTSIDE THE NUCLEUS.
HOW DO THE SUBATOMIC
PARTICLES BALANCE EACH
OTHER?
• In an uncharged atom:
• The protons = the electrons
• If 20 protons are present in an atom then 20 electrons are
there to balance the overall charge of the atom—atoms are
neutral or uncharged.
• The neutrons have no charge; therefore they do not have to
equal the number of protons or electrons.
THE PERIODIC TABLE
THE PERIODIC TABLE OF ELEMENTS ARE
BROKEN INTO 3 CATEGORIES: METALS,
NONMETALS, AND METALLOIDS.
They can
be broken
down into
10 more
specific
categories
Metals have properties (with some exceptions)
They are solid (with the exception of mercury, Hg, a liquid).
They are shiny, good conductors of electricity and heat.
They are ductile (they can be drawn into thin wires).
They are malleable (they can be easily hammered into very thin sheets).
All these metals tend to lose electrons easily. The following figure shows the metals.
NONMETALS HAVE PROPERTIES OPPOSITE THOSE OF THE
METALS.
THE NONMETALS ARE BRITTLE, NOT MALLEABLE OR DUCTILE, POOR
CONDUCTORS OF BOTH HEAT AND ELECTRICITY, AND TEND TO GAIN
ELECTRONS IN CHEMICAL REACTIONS. SOME NONMETALS ARE LIQUIDS.
METALLOIDS THE METALLOIDS, OR SEMIMETALS, HAVE PROPERTIES
THAT ARE SOMEWHAT OF A CROSS BETWEEN METALS AND
NONMETALS.
METALLOIDS TEND TO BE ECONOMICALLY IMPORTANT BECAUSE OF
THEIR UNIQUE CONDUCTIVITY PROPERTIES (THEY ONLY PARTIALLY
CONDUCT ELECTRICITY), WHICH MAKE THEM VALUABLE IN
THE SEMICONDUCTOR AND COMPUTER CHIP INDUSTRY.
EACH ELEMENT HAS A PERIOD NUMBER
AND GROUP NUMBER
The period number is
determined by the
horizontal column that
an element falls within
The group number
is determined by
the vertical
column that an
element falls
within
Where Do You Find “these” Numbers?
Atomic Number
Symbol
Name
Atomic Mass
(this is an average, always round)
electrons
protons
Atomic number equals the number of _________or
__________.
protons + ___________.
neutrons
Atomic mass equals the number of _________
HOW DO WE KNOW THE
NUMBER OF SUBATOMIC
PARTICLES IN AN ATOM?
Atomic number: this number indicates the
number of protons in an atom.
• Ex: Helium’s atomic number is 2
• So helium has 2 protons
• Ex: Carbon’s atomic number is 6
• So carbon has 6 protons
**The number of protons identifies the atom.
Ex. 2 protons = He, 29 protons = Cu
• Atomic Mass is the mass of an
atomic particle or element
WHAT ABOUT THE ELECTRONS?
• The electrons are
equal to the number
of protons (in an
uncharged/neutral
atom).
• So e- = p+ = atomic #
WHICH ELEMENT IS SHOWN?
DETERMINE THE NUMBER OF
SUBATOMIC PARTICLES IN THE
FOLLOWING:
Cl has a mass # of 35 and an atomic # of 17
p+ = ____, no = ____, e- = ____
K has a mass # of 39 and an atomic # of 19
P+ = ___,
no = ___ e- = ____