ANATOMY OF THE
PERIODIC TABLE
You might want to have a periodic table handy during the
video!
Chem-To-Go
Lesson 10
Unit 3
QUICK HISTORY
Dmitri Mendeleev
Henry Moseley
“Father of the Periodic Table”
Arranged the elements in order of
increasing atomic mass
Arranged the elements in order of
increasing atomic number
PERIODIC LAW
Columns = groups
Periodic Law - The periodic law states that certain chemical and
physical properties repeat themselves every eight elements
when the elements are arranged in order of increasing atomic
number.
Periods = rows
MAJOR CLASSIFICATIONS
• Metals
• Nonmetals
• Metalloids
PROPERTIES
Metals
•Typically solid at room
temperature
•Conduct electricity and
heat
Nonmetals
•Diverse in room
temperature state of
matter
•Non-conductors
•Shiny
•Brittle
•Malleable
•Non-lustrous
•Ductile
•Lose electrons to be
stable
•Gain electrons to
become stable
SIX IMPORTANT GROUPS
TWO IMPORTANT PATTERNS
Number of Valence Electrons = Column Number
TWO IMPORTANT PATTERNS
Common Charge of the Ion Pattern
ATOMIC RADIUS &
IONIC RADIUS
Chem-To-Go
Lesson 11
Unit 3
TRENDS
Trend = a repeating pattern
Periodic Trend = a repeating pattern on the periodic table
ATOMIC RADIUS
Definition: ½ the distance between the nuclei of two
identical touching atoms
ATOMIC RADIUS
GROUP TREND
PERIOD TREND
Period trend: [row pattern]; atomic
radius DECREASES from left to
right across a row
Group trend: [column pattern];
atomic radius DECREASES from
bottom to top of a column
WHY?
•Radius decreases across a period because the nucleus is gaining more protons to
become larger and more strongly positive. The electron cloud is drawn in by forces of
attraction.
• Radius decreases up a group because there are fewer energy levels at the top of
the periodic table.
ATOMIC RADIUS
Memory Tool
• Use a periodic table!
• Find all of the elements.
• Apply the trend.
SAMPLE MULTIPLE CHOICE:
1. Which of the following atoms will has the smallest radius?
a. Tin
b. Strontium
c. Selenium
d. Arsenic
ATOMIC RADIUS
Memory Tool
• Use a periodic table!
• Find all of the elements.
• Apply the trend.
SAMPLE MULTIPLE CHOICE:
2. Which of the following atoms will has a larger radius than calcium?
a.Aluminum
b. Copper
c. Potassium
d. None
IONS
 Cation = Positively charged ion (neutral atom has lost one or
more electrons)
 Anion = Negatively charged ion (neutral atom has gained one
or more electrons)
IONIC RADIUS
Definition: size of the ion; usually
compared to the size of its neutral atom
IONIC RADIUS
CATION RADIUS
ANION RADIUS
Cations form by losing electrons. As
electrons are lost, the ion becomes
smaller.
Anions form by gaining electrons. As
electrons are gained, the ion becomes
larger.
IONIZATION ENERGY
&
ELECTRONEGATIVITY
Chem-To-Go
Lesson 12
Unit 3
ST
1
IONIZATION ENERGY
Definition: the energy required to remove a first
electron from an atom
ST
1
IONIZATION ENERGY
ST
1
IONIZATION ENERGY
GROUP TREND
PERIOD TREND
Period trend: [row pattern];
ionization energy INCREASES
from left to right across a row
Group trend: [column pattern];
ionization energy INCREASES
from bottom to top of a column
WHY?
•The energy needed to remove an electron increases as the nucleus becomes more
strongly positive and the electrons are drawn in closer to it.
• The energy needed to remove an electron increases as the valence electrons are
closer to the nucleus. The shielding effect makes removing electrons easier from
higher energy levels.
ST
1
IONIZATION ENERGY
SHIELDING EFFECT OF CORE ELECTRONS
•The energy needed to remove an electron increases as the valence electrons are
closer to the nucleus. The shielding effect makes removing electrons easier from
higher energy levels.
ST
1
IONIZATION ENERGY
Memory Tool
• Use a periodic table!
• Find all of the elements.
• Apply the trend.
SAMPLE MULTIPLE CHOICE:
1. Which of the following atoms will has the smallest ionization energy?
a. Tin
b. Strontium
c. Selenium
d. Arsenic
ST
1
IONIZATION ENERGY
Memory Tool
• Use a periodic table!
• Find all of the elements.
• Apply the trend.
SAMPLE MULTIPLE CHOICE:
2. Which of the following atoms has a larger ionization energy than calcium?
a.Aluminum
b. Copper
c. Potassium
d. None
ELECTRONEGATIVITY
Definition: the ability of an atom in a chemical
bond to draw the bonding electrons closer to itself
ELECTRONEGATIVITY
Notice that the noble gases are NOT in the image. Since they don’t
form bonds, they have no electronegativity values.
ELECTRONEGATIVITY
Period trend: [row pattern];
electronegativity INCREASES
from left to right across a row
GROUP TREND
PERIOD TREND
Group trend: [column
pattern]; electronegativity
INCREASES from bottom to
top of a column
WHY?
•The larger and more positive nuclei on the right side of the table are more likely to
attract the bonding electrons
• An unshielded nucleus is better at attracting bonding electrons. Fewer energy
levels means more electronegativity.
ELECTRONEGATIVITY
Memory Tool
• Use a periodic table!
• Find all of the elements.
• Apply the trend.
SAMPLE MULTIPLE CHOICE:
1. Which of the following atoms will has the highest electronegativity?
a. Tin
b. Chlorine
c. Neon
d. Arsenic
ELECTRONEGATIVITY
Memory Tool
• Use a periodic table!
• Find all of the elements.
• Apply the trend.
SAMPLE MULTIPLE CHOICE:
2. Which of the following atoms will has a higher electronegativity than P?
a.Oxygen
b. Fluorine
c. Helium
d. None
ELECTRON AFFINITY
Definition: the amount of energy released when an
electron is added to a neutral atom or molecule to
form a negative ion.
Period trend: [row pattern];
electron affinity INCREASES
from left to right across a row
Group trend: [column
pattern]; electron affinity
INCREASES from bottom to
top of a column
PERIOD TREND
ELECTRON AFFINITY
Memory Tool