Transcript What are Valence Electrons

11/4 & 11/5 - 8th Grade Agenda
Learning Objective: Valence Electrons and
Bonding
Collect HW: Reading & Notetaking: p.86 – 87
Chap 4 Test
Textbook Reading p.176-182
Reading & Notetaking p.90 – 91
Reminder: Elemental Super Hero Project
Due:11/13 (15 Points)
Daily Reflection
• Prompt: Write 3 ways that we use Radio
active elements.
Atomic Number tells the number
of P___________
• Number of protons (or electrons) in the
nucleus of an atom.
As we move left to right and top
to bottom in the periodic table,
the atomic number _________
• Increases
What does an atom consist of?
• Protons and Neutrons
in the nucleus
• Surrounded by one or
more electrons
What charge does a proton
have?
• Positive Charge
What charge does a neutron
have?
• Neutral charge
What are the outer most
electrons called?
• Valence Electrons
What are Valence Electrons
• Valence electrons are
electrons that have the
highest en______
ergy level
and are held most
loosely
ber of
• The num______
valence electrons in an
atom of an element
determines its
perties and the
pro________
ways it can bond with
other atoms
In this picture, what is happening
to valence electrons?
• In a chemical bond,
electrons may be
transferred from one
atom to another or
they may be shared
between the atoms
Electron Dot Diagram
• There can be between 1 to 8 Valence
elect________.
rons
• Electron dot diagram includes the symbol
for element surr_________
ounded by dots.
Electron Dot Diagram
How many valence electron in
Sulfur?
•6
How many valence electrons are
needed to make atoms happy?
• Atoms are happiest when
they have 8 electron in
their valence shell.
• If the atom’s valence shell
happens to be the first
shell (hydrogen or Helium)
2 electrons in that shell
make them happy
Chemical Bond
• Atom react in a way
that makes each atom
more sta______.
ble
• Number of valence
electrons increase to
8 (or 2 for hydrogen)
• Chemical bond is the
force of attraction that
holds two atoms
together as a result of
rearr___________
angement of
electrons between
them.
Number of Valence Electrons determined
by place in the Periodic Table
• For elements in groups 1-2 and 13-18, the
rons
number of valence elect_________
is easy to
tell directly from the periodic table.
• For elements in group 3-12, determining the
number of valence electrons is more
compli__________.
cated
How many Valence electrons does it
have?