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The Periodic Table
Chapter 6
The Periodic Table
 The periodic table is based on chemical properties.
 Chemical behavior is determined by electron
configuration.
 The position on the table corresponds to the
electron configuration.
 Check out this website at home!
 http://center.acs.org/periodic/tools/PT.html
The Periodic Table
 Metals
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To the left of the stairs (80% of the elements)
Good conductors of heat and electric current
Solids at room temperature (except Hg)
Malleable and reflective (shiny)
 Nonmetals
 To the right of the stairs
 Most are gases at room temperature
 Properties opposite of metals
 Metalloids
 On the stairs
 Includes B, Si, Ge, As, Sb, Te, At
 Properties similar to both metals and nonmetals
Classifying the Elements
 Metals
 Alakali Metals
 Group 1A
 Alkaline Earth Metals
 Group 2A
 Nonmetals
 Halogens
 From hals meaning salt and genesis meaning to be born
 Group 7A
Electron Configurations
 Nobel Gases
 Group 8A
 Also known as the inert gas
 All have an S2P6 Configuration
 Representative Metals
 Groups 1A, 2A, and 3A
 They have valence electrons in S1,S2, and S2P1
 Transition Metals
 Have partially filled d sublevels
 Inner Transition Metals
 Have partially filled f sublevels
Covalent Atomic Radius
One half the distance betweeen nuclei of atoms in
a diatomic molecule
Atomic Size
High shielding = large atom
High nuclear pull= small atom
1. Size increases as you go
down because each row
represents one more
energy level
2. Size decreases as you go
to the right due to
increased nucleus positive
charge
3. As the atom is larger –
outer electrons can drift
away easier
4. Metals become more
reactive
5. Nonmetals become less
reactive
Group Trends
Ionization Energy
 Energy required to remove an electron from a gaseous
atom
 As we move down the group – ionization energy
decreases
 Metals become more reactive, non metals become less
reactive
 As we move across a period, nuclear pull becomes
greater – and ionization energy increases
 Metals become less reactive, non metals become more
reactive
Ionization energy
Low shielding = high ionization energy
High nuclear pull = high ionization energy
Electron Affinity/Electronegativity
 Indicates the ability of an atom to attract electrons
 As we move down a group, electron affinity is lower
 As we move across a period, nuclear pull increases and
this increases electron affinity
 Non metals have a high electron affinity
 Which element would have the least electron affinity?
 Which would have the most?
Electron Affinity and
Electronegativity
Low shielding = high electron affinity
High nuclear pull = high electron affinity
Trends In Ion Size
 Remember that generally atoms have a neutral charge:
electrons = protons
 An ion is an atom with a positive or negative charge
 This happens when electrons are transferred between
atoms
 Positive ions are called cations
 Negative ions are called anions
Trends In Ion Size
Cations are smaller
than the atoms that
they come from
Anions are larger
than the atoms
that they come
from