2. The Periodic Table
l Arrangement of the known elements
based on atomic number and chemical
and physical properties.
l Dividedinto three basic categories:
l Metals
l Nonmetals
l Metalloids
3. Basic Organization
The periodic table is organized by:
l Atomic structure
l Atomic number
l Chemical and Physical Properties
4. Uses of The Periodic Table
The periodic table is useful in predicting:
l chemical behavior of the elements
l trends
l properties of the elements
5. Atomic Structure Review
l Atoms
are made of protons,
electrons, and neutrons.
l Elements are atoms of only one type.
l Elements
are identified by the atomic
number (# of protons in nucleus).
6. Energy Levels Review
l Electronsare arranged in a region
around the nucleus called an electron
cloud. Energy levels are located within
the cloud.
l At
least 1 energy level and as many as
7 energy levels exist in atoms.
7. Energy Levels Review
l Electrons
in levels farther away from
the nucleus have more energy.
l Inner
levels will fill first before outer
levels.
8. Energy Levels & Valence Electrons
l Energy
levels hold a specific amount of
electrons:
l 1stlevel = up to 2
l 2nd level = up to 8
l 3rd level = up to 8 (first 18 elements only)
9. Energy Levels & Valence Electrons
l The
electrons in the outermost level
are called valence electrons.
l Determine reactivity - how elements will react
with others to form compounds
l Outermost level does not usually fill completely
with electrons
10. Using the Table to Identify
Valence Electrons
l Elements are grouped into vertical
columns because they have similar
properties.
l These are called groups or families.
l Groups are numbered 1-18.
11. Using the Table to Identify
Valence Electrons
l Group
numbers can help you
determine the number of valence
electrons:
l Group 1 has 1 valence electron.
l Group 2 has 2 valence electrons.
l Groups 3–12 are transition metals and
have 1 or 2 valence electrons.
12. Using the Table to Identify
Valence Electrons cont.
l Groups
13–18 have 10 fewer than the
group number. For example:
l Group 13 has 3 valence electrons.
l Group 15 has 5 valence electrons.
l Group 18 has 8 valence electrons.
13. Elements & Reactivity
l Reactivity
is a chemical property that
determines how elements will react
with others to form compounds.
14. Elements & Reactivity
l What makes an element reactive?
● Number of valence electrons each atom
has
● When outer levels are full, atoms are
stable.
● When they are not full, they react:
● gain, lose, or share 1 or 2 electrons.
15. Elements & Reactivity
l The
most reactive metals are the
elements in Groups 1 and 2.
l Elements in Group 1 need seven more electrons
to fill their outer level.
l Elements in Group 2 need six more electrons to
fill their outer level.
l Thesegroups are known as the
“givers” because they easily give up
their valence electrons to make a
compound.
16. Elements & Reactivity
l The
most reactive nonmetals are the
elements in Groups 6 and 7.
l Elements in Group 6 only need two more
electrons to fill their outer level.
l Elements in Group 7 only need one more electron
to fill their outer level.
l These
groups are known as the
“takers” because they easily receive
valence electrons to make a
compound.
17. Groups
l Groups run vertically in the periodic
table.
l They are numbered from 1–18.
l Elements in the same groups have the
same number of valence electrons in
the outer energy level.
l Grouped elements behave chemically
in similar ways.
18. Group 1: Alkali Metals
l Contains: Metals
l Valence Electrons: 1
l Reactivity: Very Reactive
l Properties:
l solids
l soft
l react violently with water
l shiny
l low density
19. Group 2: Alkaline-Earth Metals
l Contains: Metals
l Valence Electrons: 2
l Reactivity: very reactive, but less
reactive than alkali metals (Group 1)
l Properties:
l Solids
l Silvercolored
l More dense than alkali metals
20. Groups 3-12 Transition
Metals
l Contain: Metals
l Valence electrons: 1 or 2
l Reactivity: less reactive than alkali and
alkaline-earth metals
l Properties:
l Higherdensity
l Good conductors of heat and electricity
21. Groups 3-12 Transition Metals
Below Main Table
l Contain: The Lanthanide and Actinide
Series
l These two rows are pulled out of
sequence and placed below the main
table to keep the table from being too
wide.
l Lanthanides are #’s 58–71.
l Actinides are #’s 90–103.
22. Groups 3-12 Rare Earth
Elements ~ Lanthanides
l Lanthanides follow the transition metal
# 57 Lanthanum in Period 6.
l Valence electrons: 3
l Reactivity: Very reactive
l Properties:
● High luster, but tarnish easily
● High conductivity for electricity
● Very small differences between them
23. Groups 3-12 Rare Earth
Elements ~ Actinides
l Actinides follow the transition metal #
89 Actinium in Period 7
l Valence electrons: 3 (but up to 6)
l Reactivity: unstable
l All
are radioactive
l Most made in laboratories
24. Metalloids
l A zig-zag line that separates metals
from metalloids
l Elements from Groups 13–17 contain
some metalloids.
l These
elements have characteristics
of metals and nonmetals.
25. Group 13: Boron Group
l Group 13: Boron Group
l Contains: 1 metalloid and 4 metals
l Valence Electrons: 3
l Reactivity: Reactive
l Other shared properties:
l Solid at room temperature
26. Group 14: Carbon Group
l Contains: 1 non-metal, 2 metalloids,
and 3 metals
l Valence Electrons: 4
l Reactivity: Varies
l Other shared properties:
l Solid at room temperature
27. Group 15: Nitrogen Group
l Contains: 2 non-metals, 2 metalloids,
and 1 metal
l Valence electrons: 5
l Reactivity: Varies
l Other shared properties:
l All but N are solid at room temperature
28. Group 16: Oxygen Group
l Contains: 3 non-metals, 1 metalloid,
and 2 metals
l Valence Electrons: 6
l Reactivity: Reactive
l Other shared properties:
l All but O are solid at room temperature.
29. Groups 17 : Halogens
l Contain: Nonmetals
l Valence Electrons: 7
l Reactivity: Very reactive
l Other shared properties
● Poor conductors of electric current
● React violently with alkali metals to form
salts
● Never found uncombined in nature
30. Group 18 Noble Gases
l Contains: Nonmetals
l Valence Electrons: 8 (2 for He)
l Reactivity: Unreactive (least reactive
group)
l Other shared properties:
l Colorless, odorless gases at room
temperature
l Outermost energy level full
l All found in atmosphere
31. Hydrogen Stands Apart
l H is set apart because its properties
do not match any single group.
l Valence electrons: 1
l Reactivity: very, but loses the 1
electron easily
l Properties:
l Similar to those of non-metals rather than
metals
32. Periods
l Periods run horizontally across the
Periodic Table
l Periods are numbered 1–7
l All the elements in a period will have the
same number of energy levels, which
contain electrons. Examples:
l Period 1 atoms have 1 energy level.
l Period 2 atoms have 2 energy levels.
l Period 5 atoms have 5 energy levels.
33. Periods Continued
l Movingfrom left to right across a period,
each element has one more electron in
the outer shell of its atom than the
element before it.
l This
leads to a fairly regular pattern of
change in the chemical behavior of the
elements across a period.