Chemical Foundations:
Elements, Atoms, and Ions
Atoms and Ions
Atoms and Ions
Objectives:
1. Students will be able to describe the
formation of ions from their respective atoms
and be able to name them.
2. Students will be able to relate the charge of
an ion to the number of protons and
electrons.
3. Students will be able to predict which ion a
given element forms.
Class Warmup
Determine the number of protons, neutrons, and
electrons in each of the following isotopes:
3
1
H
65
30
Zn
56
Fe
Protons have (a) ________ charge.
Electrons have (a) _______ charge
Neutrons have (a) _______ charge
Atoms and Ions
What is an Ion?
• An atom that has gained or lost electrons and,
as a result has a negative or positive charge.
How does an atom become an ion?
• by gaining or losing electrons.
• Metals form + ions by losing electrons
• Nonmetals form - ions by gaining electrons
Atoms and Ions
Cation – a positively charged ion; formed when an
atom loses one or more electrons
1+
Na
has ______ protons and _____ electrons
• Cations are named using the element name
Examples:
Fe3+
iron ion
Na+
sodium ion
Atoms and Ions
Anion – a negatively charged ion; formed when an
atom gains one or more electrons
2O
has _______ protons and _______ electrons
• Anions are named by dropping the element name
ending and replacing it with “ide”.
Examples:
O2- oxide
Ffluoride
N3- nitride
Practice Problems
Find the number of protons, neutrons, and
electrons in each of the following ions.
19
9
F
24
12
Mg 2
23
11
Na 
17
8
2
14
O
N
3
Ion Charges and the Periodic Table
Ions and their Compounds
Formation of an Ionic Compound - YouTube