Good Morning!
To begin today, you will need:
1. 3 different colors of writing utensils
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colored pencils are up front for your use
2. One blank periodic table
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Up front
3. One packet of notes (green)
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Up front
The Periodic Table
&
Periodic Trends
Groups/Families
Representative Elements
Groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A
*CAS vs. IUPAC (old)
naming systems
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Periods
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6.3
Periodic Trends
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Trends in Atomic Size
The atomic radius is one half of the distance
between the nuclei of two atoms of the same
element when the atoms are joined.
Slide
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© Copyright Pearson Prentice Hall
Trends in Atomic Size
• Moving left to right, e- are added to the same
energy level, while protons are added to the
nucleus
• The e- are attracted more strongly and are
pulled in closer to the nucleus, making the
atomic size smaller.
Ions
• When an atom loses or gains electrons it becomes
an ion.
• A positively (+) charged ion is called a cation (+).
– Lost electrons, so has more protons than electrons
– Metals want to lose their valence electrons; therefore
only metals can be cations.
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• A negatively (-) charged ion is called an anion (-).
– Gained electrons, so has more electrons than protons
– Non-metals want to gain valence electrons; therefore
only non-metals can be anions.
Ions
• When atoms gain or lose electrons, they want to
get to have a “full” outer energy shell.
• The octet rule states that elements gain or lose
electrons to attain an electron configuration of
the nearest noble gas.
• Metals lose electrons to go down to the previous
energy shell, either full at 2 electrons (Li), or 8
electrons.
• Non-metals gain electrons to fill their outermost
shell to 8 electrons.
Which is bigger….
the cation or the
original atom?
Which is bigger….
the anion or the
original atom?
Trends in Ion Size
Students label trend on notes
Trends in 1st Ionization Energy
Energy generally increases
Energy generally increases
Ionization Energy:
The energy required to remove an electron from an atom.
Ionization Energies
Trends in Electronegativity
Electronegativity
The ability of an atom of an element to attract electrons
when the atom is in a compound.
Things to Remember
• Atomic Radius
– ½ the distance between the nuclei of two atoms of the same
element when the atoms are joined
• Ions
– Cation is a positively (+) charged ion (more protons than
electrons)
– Anion is a negatively charged ion (more electrons than
protons)
• Ionic size
– Cations are always smaller than the atoms from which they
form
– Anions are always larger than the atoms from which they
form
• The trends that exist among these properties can be
explained by variations in atomic structure.