Drawing Atoms and Chemical Bonding
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Transcript Drawing Atoms and Chemical Bonding
Drawing Atoms & Chemical
Bonding
April 13, 2015
Electron Energy Levels
Electrons are arranged in
within the electron cloud.
Each energy level can hold a certain
maximum number of electrons.
2
First level – ____
8
Second level – ____
8
Third level – ____
Drawing an Atom
Fluorine Atom (F)
9P
10 N
How many
electrons
does a
Fluorine
atom have?
9
_______
Electron Energy Levels
most stable atoms have the
The
outermost energy level filled.
Atoms in which the outermost energy level
is filled does not easily gain or lose
electrons, therefore they do not easily form
compounds with other elements.
____________ electrons represent the
number of electrons in the outer energy
level.
Drawing an Atom
I’m
Stable
Neon Atom (Ne)
10 P
10 N
Go away, I
don’t want to
BOND with
anyone.
How many
electrons
does a
Neon atom
have?
10
_______
CHEMICAL BONDS
When two or more elements come
together, they form a compound.
Compounds are held together by forces
called chemical bonds.
Atoms can form chemical bonds by
sharing electrons or by transferring
electrons from one atom to another.
Types of Bonds
When a compound is formed through the
transfer of electrons, this is called an ionic
bond.
Most ionic compounds are formed by the
transfer of electrons from a metal to a
nonmetal.
When an atom loses an electron to move to
another atom, it ends up with more protons than
positive
electrons. This results in an overall __________
charge.
Types of Bonding
When an atom gains an electron from
another atom, it ends up with more
electrons with protons. This results in an
negative
overall ___________
charge.
Ions – electrically charged atoms.
(Ex) Na+ or Cl
Cl
Now, the Na gives
or transfers its one
extra electron to Cl
Na
17P
11P
18N
12N
Types of Bonding
Covalent bond – a bond based on the
attraction between atoms that share
electrons.
(Ex) Water –H2 O
Covalent Bonding (Water Molecule)
H 2O
1P
Hydrogen
8P
Hydrogen
8N
1P
Oxygen
Review Questions
In water, how many electrons does oxygen
share with each hydrogen atom? One
What kind of bond is this? Covalent Bond
How many valence electrons does sodium
have? One
How many valence electrons does
chlorine have? Seven
Describe what happens when sodium
bonds with chlorine.
Review Questions
What kind of bond is formed between Na
and Cl? An Ionic Bond
After the bond between sodium and
chlorine forms, how many electrons does
sodium have in the resulting outer layer?
Eight
What is the charge of a teaspoon of salt
(NaCl) crystals? Explain. Neutral