Transcript Periodic Trends

Periodic Trends 6.3
Slide
1 of 31
6.3
Periodic Trends
Sodium chloride (table salt)
produced the geometric
pattern in the photograph.
Such a pattern can be used
to calculate the position of
nuclei in a solid. You will
learn how properties such
as atomic size are related to
the location of elements in
the periodic table.
Slide
2 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Atomic Size
Trends in Atomic Size
What are the trends among the elements
for atomic size?
Slide
3 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
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
4 of 31
© Copyright Pearson Prentice Hall
Periodic Trends
>
Slide
5 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Atomic Size
Group and Periodic Trends in Atomic Size
In general, atomic size increases from
top to bottom within a group and
decreases from left to right across a
period.
Slide
6 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Atomic Size
Slide
7 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Atomic Size
Slide
8 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Ions
Ions
How do ions form?
Slide
9 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Ions
Positive and negative ions form when
electrons are transferred between atoms.
Slide
10 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Ions
Positive and negative ions form when
electrons are transferred between atoms.
Slide
11 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Ions
Some compounds are composed of particles
called ions.
• An ion is an atom or group of atoms that has
a positive or negative charge.
• A cation is an ion with a positive charge.
• An anion is an ion with a negative charge.
Slide
12 of 31
© Copyright Pearson Prentice Hall
Periodic Trends
>
Ions
Animation 7
Discover the ways that atoms of elements
combine to form compounds.
Slide
13 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionization Energy
Trends in Ionization Energy
What are the trends among the elements
for first ionization energy, ionic size, and
electronegativity?
Slide
14 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionization Energy
The energy required to remove an electron from
an atom is called ionization energy.
• The energy required to remove the first
electron from an atom is called the first
ionization energy.
• The energy required to remove an electron
from an ion with a 1+ charge is called the
second ionization energy.
Slide
15 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionization Energy
Group and Periodic Trends in Ionization
Energy
First ionization energy tends to
decrease from top to bottom within a
group and increase from left to right
across a period.
Slide
16 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionization Energy
Slide
17 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionization Energy
Slide
18 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionization Energy
Slide
19 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionic Size
Trends in Ionic Size
During reactions between metals and
nonmetals, metal atoms tend to lose electrons,
and nonmetal atoms tend to gain electrons. The
transfer has a predictable effect on the size of
the ions that form.
Slide
20 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionic Size
Cations are always smaller than the
atoms from which they form. Anions are
always larger than the atoms from
which they form.
Slide
21 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionic Size
Relative Sizes of Some Atoms and Ions
Slide
22 of 31
© Copyright Pearson Prentice Hall
Periodic Trends
>
Slide
23 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Ionic Size
Size generally increases
Trends in Ionic Size
Slide
24 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Electronegativity
Trends in Electronegativity
Electronegativity is the ability of an atom of an
element to attract electrons when the atom is in a
compound.
In general, electronegativity values
decrease from top to bottom within a
group. For representative elements, the
values tend to increase from left to
right across a period.
Slide
25 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Trends in Electronegativity
Representative Elements in Groups 1A through 7A
Slide
26 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Summary of Trends
Summary of Trends
What is the underlying cause of periodic
trends?
Slide
27 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
>
Summary of Trends
The trends that exist among these
properties can be explained by
variations in atomic structure.
Slide
28 of 31
© Copyright Pearson Prentice Hall
6.3
Periodic Trends
Summary of Trends
Increases
Decreases
Constant
Increases Decreases
Size
Electronegativity
Ionic
Atomic
Nuclear
Shielding
Ionization
of
size
cations
Size
anions
Charge
energy
>
Slide
29 of 31
© Copyright Pearson Prentice Hall
Periodic Trends
*
*
*
>
* * * *
*
© Copyright Pearson Prentice Hall
*
Slide
30 of 31