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CHEMISTRY!!!
Yeah baby!
Structure of the Atom
Nucleus: The
center of an atom.
Holds the protons
and neutrons.
Structure of the Atom:
Protons: Positive
charge, atomic
number
Neutrons: no charge
Both found in the
Nucleus!
Structure of the Atom
Electrons: Negative
charge, orbit the
nucleus
Structure of the Atom
Atoms on the periodic
table have 2 numbers
Structure of the Atom
Atomic mass: mass of
both the neutrons and
protons.
Protons = 1
Neutrons = 1
Structure of the Atom
Atomic number:
Number of protons
Protons tell you
what atom it is!
Structure of the Atom
Isotopes: When the
number of neutrons
differ, changing the
atomic mass, BUT
atomic number stays
the same!
Structure of the Atom
Carbon
Electron shell
Shells:
st
1 shell = 2
electrons
nd
2 shell = 8
electrons
Electron shell
Complete Shell:
no empty sites,
full electron count
in shell.
Element vs. Compound
Element: same
kind of atom
Compound: made
up of mixed
elements
Chemical Bonding
There are three types
of major bonds:
Ionic
Covalent
Hydrogen
Chemical Bonding
The bonds are
determined by
differences in
electronegativity
(power of an atom to
attract electrons).
Chemical Bonding
Ionic: Atom Gives
(takes) an electron
from another atom
and then becomes
shell complete.
Chemical Bonding
Ionic: One becomes
positively charged
and one becomes
negatively charged.
(Electroneg is ≥ 1.7)
Na
Cl
Na-Cl
Chemical Bonding
Covalent: 2 atoms
share an electron to
become shell complete.
It is a stronger bond
then Ionic.
(Electroneg is ≤ 1.6)
H =
O =
H-O-H
Chemical Bonding
Hydrogen Bond:
Bond formed when
hydrogen is in covalent
bond with another
element, because of
unequal sharing of
electrons.
Chemical Bonding
Hydrogen Bond:
Atoms become polar
with Hydrogen side
having a slight positive
side. Allowing a weak
bond with negative ion.
Practice:
 Worksheet.
Some Atoms are Sociable, Others Aren’t
Atoms “want” (are most stable) to have a filled outer electron
shell.
Atoms without a filled
outer shell will share
electrons with other
atoms to accomplish
this “goal.”
Filling outer electron
shells controls which
atom will pair with
which others and in
what combinations.
Filling Electron Shells
An important rule: the innermost
shell holds two electrons;
subsequent shells hold 8
electrons.
Pairing for the Greater Good
When atoms come together by sharing electrons the bond is
a covalent bond.
H2
A molecule is formed when two or more atoms are bound together