This document defines key terms related to chemical bonds and discusses how atoms bond to achieve stable electron configurations. It explains that atoms form ions by gaining or losing electrons to achieve a full outer electron shell like noble gases. Metals typically lose electrons to form positive ions while nonmetals gain electrons to form negative ions. These oppositely charged ions then form ionic bonds. The document also describes how nonmetal atoms can form covalent bonds by sharing electrons to achieve full outer shells. Polyatomic ions, which are groups of bonded atoms that act as a single unit, are presented and examples are given of how they form ionic bonds with metals through electron transfer.

1. Atoms

2. Vocabulary
● Ion
● Valence Electrons
● Electron Orbitals
● Neutral Atom
● Chemical Bond
● Ionic Bond
● Covalent Bond
● Polar Covalent Bond
● Nonpolar Covalent Bond
● Polyatomic Ion
● Electronegativity
● Molecule
● Double Bond
● Triple Bond

3. Chemical Bonds

6. All elements want to have a complete set of valence electrons; elements will react until they
have a complete set. A complete set consists of eight electrons, this explains why Noble gases do
not react. Helium is a Noble gas, even though its outer shell only has two electrons. Helium outer
shell only accepts two electrons, therefore its set of valence electrons is complete; it will not react.

7. ***Pg 58 & 59

8. Ions
Atoms may lose or gain electrons in order to have a complete outer shell.
When an element loses an electron(-), it becomes positively charged. This is
because it now has more protons (+) than electrons (-).
Conversely, when an element gains an electron(-), it becomes negatively
charged. This is because it now has more electrons (-) than protons (+) .

9. Valence Electrons & Ions
The number of electrons lost, or
gained, depends on the valence
electrons of the element. (The
outer shell)
Sodium has one valence electron(outer
shell), and the shell beneath has eight. If it
loses the one valence electron, the shell
underneath becomes the outer shell with
eight electrons.
The same concept applies to Magnesium.
The difference is that Magnesium has two
valence electrons.

10. Valence Electrons & Ions
Nature is lazy…
Chlorine
Imagine you have to pay 1,000$
pesos to move each electron.
Electron Store
. . . . . . . .
Calcium can: 1 move two away and
leave the shell beneath with eight
electrons, or (2) it can move six to
itself.
Option 1 - 2,000$
Option 2 - 6,000$ Option 1 - 7,000$
Chlorine can: (1) move seven away
and leave the shell beneath with
eight, or (2) it can move one to itself.
Option 2 - 1,000$

11. Valence Electrons & Natural Ions
Metals and transitional metals have a small
number of valence electrons
*Remember the group
number tells you the number of valence
electrons the element has.
Metals lose electrons because they cannot
“afford” to gain a large number of electrons.
Calcium does not have enough protons to attract
six electrons.

12. Valence Electrons & Natural Ions
Nonmetals have a large number
of valence electrons. Nonmetals tend
to complete their outer shell by
attracting electrons from other
elements with their protons.
*Remember the group number tells you the
number of valence electrons the element has.
Chlorine only needs one more electron to
complete its outer shell.

13. Natural Ions
Atoms may lose or gain electrons in order to have a complete outer shell.
When an element loses an electron(-), it becomes positively charged. This is
because it now has more protons (+) than electrons (-).
Conversely, when an element gains an electron(-), it becomes negatively
charged. This is because it now has more electrons (-) than protons (+) .

14. Valence Electrons & Natural Ions
Atoms may lose or gain electrons in order to have a complete outer shell.
In summary, the ion that an atom forms depends on its valence electrons
*(Identifiable by the atoms group number).
This will determine the type of bonds the atom will form.

15. Chemical Bonds: Ionic

16. ● Metal + Nonmetal
○ Na + Cl NaCl (Chemical Change? Pure Substance?)
■ Sodium (*Metal) losses an electron and become a cation Na+
■ Calcium (Nonmetal) gains an election and becomes an anion Cl-
■ These changes allow both Na and Cl to have 8 electrons in
their outermost shells
Ionic Bonds

18. Draw Lewis Dot Structure
CaF2 :
BeF2
Natural Ions Be, F ?
Draw the Lewis Dot Structure of the
following Ionic Bonds:

19. Subscripts
The subscripts following each element’s symbol represent how many
atoms of that element are present in the molecule formed.
In the molecule BeF2 , there is one
Beryllium atom and two Fluorine atoms.
You can determine the subscripts by
exchanging them with the superscripts of
the natural ions of the elements involved.
Natural Ions Chemical Formula
Be2+ F1- BeF2

20. Covalent Bonds
When two neutral nonmetals share electrons they form a covalent bond.
**NOT Ions
In covalent bonds, atoms do not lose nor gain electrons; they
share them in order to complete their valence electrons.

21. CH4 ClH
NH3
Methane has four Hydrogen atoms, Hydrogen Chloride has one, and
Ammonia has three. Why??
Elements rarely exist on their own; they normally have reacted with another
element, sometimes with an identical atom. Only Noble Gases exist
unbonded to another element. Why??

22. Subscripts
The subscripts following each element’s symbol represent how many
atoms of that element are present in the molecule formed.
In the molecule H2O, there are two
Hydrogen atoms and one Oxygen atom.
You can determine the subscripts by
exchanging them with the superscripts of
the natural ions of the elements involved.
Natural Ions Chemical Formula
H1+ O-2 H2O

23. Polyatomic Ions
A polyatomic ion is an ion formed with two or more atoms.
When a covalent bond (Two or more Nonmetals) forms, and the
resulting number of electrons and protons is not equal, an ion with two or
more atoms is formed.
(OH)- (CN)-
(NH4)+

24. Polyatomic Ions
Polyatomic
Ion
Hydroxide Cyanide Ammonium
Protons (+) 6 (O) + 1 (H) = 7+ 4 (C ) + 1 (N) = 5+ 5(N) + 4 (H) = 9+
Electrons (-) 6(O) + 1 (H) + 1 (?) = 8- 4 (C ) + 5 (N) + 1 (?) = 10- 5(N) + 3 (H) = 8-
Charge 1- 3- 1+
Once polyatomic ions have formed, they “act” as one atom and form ionic bonds with metals.
**Ionic bonds with polyatomic ions work the same way as ionic bonds between metals and
nonmetals.

26. Ionic Bonds with Polyatomic Ions
K(NO3) Ca(OH)2 (NH4)2(CO3)
I
K+ Ca2+ (NH)+
4O
N
(NO)- (OH)- (CO)2-
S
33**Like “regular” ionic bonds, the number of atoms present and the
combination in ionic bonds with polyatomic ions depends on the type
of ion each atom and polyatomic molecule forms.

27. Ionic Bonds with Polyatomic Ions
**Like “regular” ionic bonds, the number of atoms present and the
combination in ionic bonds with polyatomic ions depends on the type of
ion each atom and polyatomic molecule forms.
In English….
Do these combinations equal 0??
3+ 2- = 1+
1+ 2- = 1-
4+ 1- = 3+
1+ 1- = 0
2+ 1-x2 (2-) = 0
1+x 2(2+) 2- = 0
Atoms want to be happy. To be happy they
need to be neutral, have no charge. They
combine with other atoms until they are
happy(have no charge).
Atoms do not quit easily; they form
complicated combinations as long as they
can be happy.

28. Ionic Bonds with Polyatomic
1+ 1- = 0
2+ 1-x2 (2-) = 0
1+x 2(2+) 2- = 0
K+ (NO3)- = K(NO3)
Ca2+ (OH)- = Ca(OH)2
(NH4)+ (CO3)2- = (NH4)2(CO3)
Ions

29. Subscripts (Ionic Bonds with Polyatomic Ions)
The subscripts following each element’s symbol represent how many
atoms of that element are present in the molecule formed.
In the molecule Ca(OH)2, there is one
Calcium atom and two Hydroxide
molecules.
You can determine the subscripts by
exchanging them with the superscripts of
the ions of the atoms and molecules
involved.
Ions Chemical Formula
Ca2+ (OH)-1 Ca(OH)2