Chapter 5 Review
• Play slide show.
• Correct answer appears in blue.
Which has a
higher Ionization Energy?
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Al
Ca
Ba
Pt
Nd
F
Ne
Cl
Ba
Cs
Pd
Gd
Br
Xe
Which has a
larger Atomic Radius?
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Al
Ca
Ba
Pt
Nd
F
Ne
Cl
Ba
Cs
Pd
Gd
Br
Xe
Which has a smaller radius?
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Na K
F Br
Mg F
Cs Ag
Nb S
O
Se
Al
B
Pt
Ne
Which has a lower
electronegativity?
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Na K
F Br
Mg F
Cs Ag
Nb S
O
Se
Al
B
Pt
Ne
Example 1-Try to arrange the
following in order of increasing
atomic Radius.
• Try this: Be, Ba, Sr,
Answer
• Be, Sr, Ba
Example 2-Try to arrange the
following in order of decreasing
atomic Radius.
• Try this:
• Co, Cu, Se, Cs
Answer
• Cs, Co, Cu, Se
Example 3-Put the following in
order of decreasing ionization
energy
• As, Se, Cl, Br
Answer
• Cl, Br, Se, As
Example 4- Put the following in
order of increasing electronegativity
• Cd, P, S, F, O
Answer
• Cd, P, S, O,F
Example 5-Please arrange the
following in order of increasing
electron affinity.
• Al, B, Ga, C, F, N
Answer
• Ga, Al, B, C, N, F
Shielding and Nuclear Charge
• Shielding explains family trends. As you
move down a family, there are more
energy levels. More energy levels means
the valence electrons are further away
from the nucleus. With more energy
levels, the radius is larger and the
electrons are more easily removed,
meaning a lower Ionization energy.
• Example: Li has a smaller radius and
larger ionization energy than Na.
• Nuclear charge explains period trends. As
you move across a period, the energy
level stays the same, what changes is the
number of protons and electrons. With
more protons, the electrons are pulled in
closer, resulting in a smaller nucleus,
making it more difficult to remove an
electron (thus a higher IE).
• Example: Li has a larger radius and lower
ionization energy than Be.
Questions on whiteboards
• How did Mendeleev demonstrate that his
periodic table was valid or useful?
He was able to predict properties of unknown elements
• What did Moseley’s work contribute to the
development of the periodic table?
He used atomic number to organize the periodic table
• Why do elements in a group have similar
properties?
They have the same number of valence electrons.
• Sketch the general shape of the periodic
table and label the s-, p-, d-, and f- blocks.
• A chemistry experiment calls for a
compound that supplies ions of bromine,
but unfortunately this compound is not
available. Ruth substitutes a compound
that supplies ions of chlorine. Betsy uses
a compound that contains selenium. From
what you know about the periodic table,
who will have a more successful
experiment? Why?
Ruth can use chlorine because it is in the same family as bromine,
and therefore will have similar properties.
• The energy change from an added
electron is called ______________.
Electron affinity
• Why does atomic radius decrease as you
move from left to right across a period?
The elements are in the same energy level, but are adding one
proton as you move from left to right. The greater the number
of protons, the greater the positive charge. With a greater
positive nuclear charge, there is more attraction between the
electrons and protons, pulling the electrons in closer.
• Why do atoms become smaller as positive
ions?
They lose electrons (usually valence electrons).
• Why do atoms get bigger as negative
ions?
They gain electrons.
• Why are there no electronegativity values
for noble gases?
Electronegativity is the tendency of atoms to attract electrons in a
bond. Since noble gases do not react and do not form bonds,
we cannot measure electronegativity.
• Distinguish between a cation and an
anion.
Cations are positive and become smaller.
Anions are negative and become bigger.
• Identify the least and most electronegative
atoms on the periodic table.
Francium (#87) is the least electronegative.
Fluorine (#9) is the most electronegative.
(He is a noble gas and therefore has no electronegativity value)
• In the modern periodic table, elements are
arranged according to _________.
Atomic number
• Why are Group 17 elements, the
halogens, the most reactive nonmetals?
They only need one electron to have a full set of valence
electrons and become stable like the noble gases.
• As you move from left to right across
period 3 from Mg to Cl, the energy needed
to remove an electron from an atom
____________.
increases
• In which family is Ca?
Alkaline earth metals
• In which family is At?
halogens
• In which family is Xe?
Noble gases
• In which family is Cs?
Alkali metals