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