P. Sci.
Unit 8
Periodic Table
Chapter 5
Periodic Law
• Properties of elements tend to
change in a regular pattern
when elements are arranged
in order of increasing atomic
number, or number of protons
in their atoms.
Periodic Table
The periodic table is arranged in• Periods (horizontal) rows
–There are 7 periods
• Groups families (vertical)
columns
–There are 18 columns
Metals
• all elements on the left side of the
table (except Hydrogen)
Non - Metals
• all elements on the right side of
the table
Hydrogen
• Hydrogen (1) – 90% of the atoms
in the universe – (diatomic – two
atoms of the same element in a
covalent bond – H,N,O). Very
reactive, both covalent and ionic
bonds can form
Metalloids
• elements that share both
metal and non-metal
characteristics – the
elements on both sides
of the stair-step line
except aluminum.
• Also called
semiconductors
Alkali Metals
• (Column 1 except
Hydrogen) – the most
reactive group – do not
occur in nature in their
elemental form. Has one
electron in its outer energy
level
• All (including hydrogen)
have 1 valence electron.
H
hydrogen
Alkaline Earth Metals
• (Column 2) – also
reactive – also do not
occur in nature alone
(fireworks)
• 2 valence electrons.
Li
Na
K
Rb
Transition Elements
• (Columns 3 – 12) stable
metals – occur in natural state.
• usually have 2 – 3 valence
electrons to give up to form
bonds.
Mixed groups
• Boron group (13) –
mixed with both
metals and nonmetals.
• 3 valence electrons
Mixed groups cont.
• Carbon group (14) –
mixed with both
metals and nonmetals.
• 4 valence electrons
Mixed groups cont.
• Nitrogen group (15)
– mixed – tend to
share to form
covalent bonds –
fertilizers.
• 5 valence electrons
Mixed groups cont.
• Oxygen group (16) –
mixed
• 6 Valence electrons
Halogens
• (17 – all nonmetal) –
very reactive in their
element form. If
combined with a metal
forms salt. Many are
diatomic (F,Cl,Br) Br –
only nonmetal liquid.
• 7 valence electrons
Noble Gases
• (18)– Most stable because outer
layer is full. No known natural
compounds. Helium gas, neon /
argon in neon lights, argon /
krypton in electric light-bulbs, used
to produce lasers
• 8 valence electrons (full shell)
Other Groups
• Iron Triad – Iron, Cobalt, and
Nickel – create steel and other
metal mixtures.
Other groups cont.
• Coinage group –
Copper, Silver, and Gold
– stable and malleable
and found in nature –
used to make coins.
Other groups cont.
• Coating metals / Zinc
group – Zinc, Cadmium,
and Mercury – used to
coat or plate other metals
– Mercury only liquid
metal (cadmium and
mercury used in
batteries.)
Other groups cont.
• Lanthanide series –
elements 58 – 71
• Actinide series –
elements 90 – 103
• Transuranium –
all elements over 92
Allotropes
• (recall isotopes) – materials
made of the same element
that have different molecular
structure.
Diamonds
Graphite
S-113
• What is the periodic Table?
• How is it arranged?
S-116
• What subatomic structure is reflected in the
periodic table?
Unit 5 The Periodic Table
SPS4 Students will investigate the arrangement of the Periodic Table
a. Determine the trends of the following
Number of valence electrons
Types of ions formed by representative elements
Location of metals, nonmetals, and metalloids
Phases at room temperature
b. Use the Periodic Table to predict the above properties for representative elements
5.1 Organizing the Elements
How did Mendeleev organize the elements in
his periodic table?
What evidence helped verify the usefulness of
Mendeleev’s table?
5.1 Organizing the Elements
How did Mendeleev organize the elements in his periodic table?
• 1860 Mendeleev organizes the periodic table
– Rows (called periods) by increasing mass
• Later by atomic number
– Columns (called groups or families) by similar
chemical and physical properties
– Periodic – means that properties repeat at regular
intervals
– Only knew 63 elements
• He predicted the properties of blanks in his periodic
table
5.1 Organizing the Elements
What evidence helped verify the usefulness of Mendeleev’s table?
• Mendeleev predicted elements
– Eka-aluminum (one below aluminum)
• Soft metal with a low melting point and a density of
5.9 g/cm3
• 1875 Gallium (Ga) discovered
– Soft metal, melting point 29.7oC, density of 5.91 g/cm3
• Proved the patterns could be used to predict elements
S-118
• What two characteristics are used to
organize the modern periodic table?
5.2 The Modern Periodic Table
How is the modern periodic table organized?
What does the atomic mass of an element depend on?
What categories are used to classify elements on the periodic
table?
How do properties vary across a period in the periodic table?
5.2 The Modern Periodic Table
How is the modern periodic table organized?
• Periodic Law
– Elements are arranged in order of increasing
atomic number (protons)
– Period – rows on the periodic table
• As the row number increases outside electrons are in
higher energy levels
• First energy level hold 2 – so hydrogen and helium
have electrons in first energy level
• Second energy level holds 8 – so second row has eight
elements
5.2 The Modern Periodic Table
How is the modern periodic table organized?
• Periodic Law
– Properties of elements repeat in predictable ways
and are used to place element in columns
– Group – columns
• Numbered 1-18
• Some have names
–
–
–
–
1
2
17
18
alkali metals
alkaline earth metals
halogens
noble gases
5.2 The Modern Periodic Table
What does the atomic mass of an element depend on?
• Atomic Mass
– Measured in atomic mass units (u)
• One twelfth of the mass of Carbon-12
– Average Atomic Mass - calculated using
weighted averages
• The abundance of an isotope (add up to 100%)
• Mass of each different isotope
5.2 The Modern Periodic Table
What categories are used to classify elements on the periodic table?
• Elements are classified in three ways
– Natural vs Man made
• Technetium (Tc)
• All elements above 92
5.2 The Modern Periodic Table
What categories are used to classify elements on the periodic table?
• Elements are classified in three ways
– State of Matter at room temperature
• Liquids – Hg, and Br
• Gases – Group 18, H, N, O, F, Cl
• Solids – the rest of the elements up to 92
5.2 The Modern Periodic Table
What categories are used to classify elements on the periodic table?
• Elements are classified in three ways
– Metals, Non-Metals, Metalloids
• Metals Left of zig-zag line
– Transition Metals – group 3-12
• Non-Metals – right of zig-zag line
• Metalloids – touch the zig-zag line, except Aluminum
5.2 The Modern Periodic Table
How do properties vary across a period in the periodic table?
• Changes in properties across a periodic table
– From left to right
• Become less metallic, more nometallic
• More likely to gains electrons, less likely to lose them
S-119
• For the element Iron, answer the following
questions
• 1. metal, nonmetal, metalloid?
• 2. state of matter at room temperature?
• 3. average atomic mass?
• 4. name of group?
• 5. period?
5.3 Representative Groups
Why do the elements in a group have similar
properties?
What are some properties of the A groups in
the periodic table?
5.3 Representative Groups
Why do the elements in a group have similar properties?
• Valence Electrons
– Electrons in the highest occupied energy level
– Major factor in chemical reactions
– Elements in the same group, have the same
valence electrons
5.3 Representative Groups
What are some properties of the A groups?
• Alkali Metals
–
–
–
–
–
Group one
1 valence electron
React by losing 1 electron
Gain a positive charge
Highly reactive
5.3 Representative Groups
What are some properties of the A groups?
• Alkaline Earth Metals
–
–
–
–
–
Group two
2 valence electrons
React by losing 2 electron
Gain a positive charge
Less reactive
5.3 Representative Groups
What are some properties of the A groups?
• Boron Family
–
–
–
–
Group 13
3 valence electrons
React by losing 3 electron
Gain a positive charge
5.3 Representative Groups
What are some properties of the A groups?
• Carbon Family
– Group 14
– 4 valence electrons
– React by sharing electrons
5.3 Representative Groups
What are some properties of the A groups?
• Nitrogen Family
–
–
–
–
Group 15
5 valence electrons
React by gaining electrons
Gain negative charge
5.3 Representative Groups
What are some properties of the A groups?
• Chalcogens (Oxygen Family)
–
–
–
–
–
Group 16
6 valence electrons
React by gaining electrons
Gain negative charge
More reactive
5.3 Representative Groups
What are some properties of the A groups?
• Halogens
–
–
–
–
–
Group 17
7 valence electrons
React by gaining electrons
Gain negative charge
Very reactive
5.3 Representative Groups
What are some properties of the A groups?
• Noble Gases
– Group 18
– 8 valence electrons
– Do not react or form compounds
5.3 Representative Groups
What are some properties of the A groups?
• Transition Metals (Transition Elements)
– Group 3-12
– 2 valence electrons
– Additional electrons are filling lower energy
levels
– All have similar properties
– What we think of as “Metals”
5.3 Representative Groups
What are some properties of the A groups?
• Actinide and Lanthenide Series
– No group number
– 2 valence electrons
– Additional electrons are filling lower energy
levels
– Very few things that we deal with on a regular
basis