Transcript Chapter1.1D[1]

Introduction to Chemistry
Unit D Chapter 1.1
NCSCOS 4.01 and 4.02
Basic Chemistry
• Everything around you is made up of
either MATTER or ENERGY.
• MATTER is anything with mass and
volume, no matter the size.
• The periodic table is a summary of all
ELEMENTS in the universe, which make
up MATTER.
• An ELEMENT is the most basic kind
of matter and CAN NOT be broken
down into simpler substances.
ELEMENTS are pure.
Periodic Table of ELEMENTS
• The current Periodic Table has 118 Elements 92 occur naturally, the other 26 are
SYNTHETIC elements = man-made.
All Matter is made of ATOMS
• Atoms are tiny particles that
make up matter; atoms are
the smallest form of
elements; atoms of 1 type=
own element
(“basic…pure”)
• Ex: All the atoms of gold are
identical & all the atoms of
silver are identical, but the
atoms of gold are very
different from silver.
• Atoms are made up of even
smaller particles!
Did YOU Know?????
• It would take
YOU about
500 years to
count the #
of atoms in a
grain of salt!
….o my!
•contains
millions
of atoms!
Most Common Elements
• Universe = Hydrogen (about 90% of total
mass of Universe)
• Humans = Carbon, Hydrogen, Oxygen,
Nitrogen
• Humans are 61-65% Oxygen!
•“CHON”
Atomic Structure
3 Subatomic Particles:
1.
PROTONS: POSITIVELY
charged particles (p+)
2.
NEUTRONS: Uncharged or
NEUTRAL particles /NO
charge
3.
ELECTRONS:
NEGATIVELY charged
particles (e-)
*PROTONS and NEUTRONS are
always found together in the
NUCLEUS
*ELECTRONS will always orbit around
the nucleus in the ELECTRON
CLOUD (TVs,
computers…images created by
moving electron beam)
Overall charge of nucleus = +
Overall charge of electron cloud = ---
***Opposite charges attract & Like
charges repel!!***
Atomic Structure
Elements are identified
• by : Atomic Numberthe # of PROTONS in
an atom (ex: H - 1)
• All elements have a
different Atomic
Number (unique!),
Atomic Number never
changes!
• Atomic Mass Number= # of protons and
neutrons in an atom
• The nucleus holds the
MASS!
Isotopes
ISOTOPES: atoms of the same
element with a different # of
NEUTRONS.
To find ATOMIC MASS # OF
ISOTOPES:
Add PROTONS + NEUTRONS
EX: Chlorine atoms – 17
protons
However..some Cl atoms
have 18 neutrons; some
have 20 neutrons
Interpret a Square on the
Periodic Table
• Elements go in order based
on Atomic Number (= # of
protons)
• Symbol & Name
• Atomic Mass = protons +
neutrons, decimal because
it is average of all isotopes
of element
• Electrons = same # as
Protons (if neutral atom!)
• To find # of neutrons:
SUBTRACT Atomic # from
Atomic Mass # (rounded)
When Atoms have….
EQUAL # of ELECTRONS & PROTONS
( e = - ; p = + ) SO….NO overall electrical charge!!!
When Atoms have…
DIFFERENT # of ELECTRONS & PROTONS form an ION
so…DOES have an overall electrical charge
IONS are formed when ATOMS GAIN
or LOSE
ELECTRONS!!