# 10/14/13 Unit 4: Periodic Table Trends

```Periodic Table Trends
• Half the distance between the nuclei of two
identical atoms bonded together
• Across a Period= DECREASES
▫ As you add more protons, the attractive force of
the nucleus increases, pulling electrons in more
closely
• Down a Group=INCREASES
▫ As you add more energy levels, the size of the
electron cloud increases
Which of the elements would have
84%
11%
ne
s
ag
12
-M
fu
r
iu
m
e
or
in
17
-C
hl
co
n
0%
14
-S
ili
m
in
um
0%
5%
16
-S
ul
13-Aluminum
14-Silicon
17-Chlorine
12- Magnesium
16-Sulfur
13
-A
lu
1.
2.
3.
4.
5.
Ionization Energy
• The energy required to remove one electron
from a neutral atom.
▫ High I.E. – Harder to lose
electrons
▫ Low I.E. –Easier to lose
electrons
Ionization Energy
Ionization Energy
• Across a Period=INCREASES
▫ Electrons are closer to nucleus, therefore harder to
remove
• Down a Group=DECREASES
▫ Electrons are farther from the nucleus, therefore
easier to remove
Which element would have the lowest
ionization energy?
0%
68%
26%
5%
0%
1.
2.
3.
4.
5.
20- Calcium
56- Barium
4- Beryllium
38- Strontium
12-Magnesium
Electron Affinity
• The energy released when a neutral atom
acquires an electron.
• Elements that really want another electron tend
to release more energy (higher E.A.)
Across a period= INCREASES
Down a group= DECREASES
Electronegativity
• The ability of an atom to attract electrons
• The most electronegative element is fluorine
Across a Period=
INCREASES
Down a Group=
DECREASES
Which of the elements would have
the highest electronegativity?
84%
13-Aluminum
14-Silicon
17-Chlorine
12- Magnesium
16-Sulfur
11%
12
-M
fu
r
5%
16
-S
ul
ag
ne
s
or
in
iu
m
e
0%
17
-C
hl
co
n
14
-S
ili
m
in
um
0%
13
-A
lu
1.
2.
3.
4.
5.
METALS vs NONMETALS
•
•
•
•
•
•
METALLIC CHARACTER
Lower I.E. (tend to lose e-)
Lower E.N. (don’t want e-)
High Luster (shiny!)
Good Conductors
Malleable and Ductile
• MOST METALLIC ELEMENT:
• NONMETALLIC
CHARACTER
• High I.E. (don’t want to lose e-)
• High E.N. (tend to gain e-)
• Dull (no luster)
• Poor Conductors
• Brittle as solids
• MOST NONMETALLIC
ELEMENT:
Which of the elements would be the
least reactive metal?
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
fu
r
0%
16
-S
ul
ne
s
or
in
iu
m
e
0%
ag
4
0%
12
-M
3
14
-S
ili
m
2
13
-A
lu
1
0%
co
n
0%
17
-C
hl
13-Aluminum
14-Silicon
17-Chlorine
12- Magnesium
16-Sulfur
in
um
1.
2.
3.
4.
5.
19
20
Which of the elements would be the
most reactive nonmetal?
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
fu
r
0%
16
-S
ul
ne
s
or
in
iu
m
e
0%
ag
4
0%
12
-M
3
14
-S
ili
m
2
13
-A
lu
1
0%
co
n
0%
17
-C
hl
13-Aluminum
14-Silicon
17-Chlorine
12- Magnesium
16-Sulfur
in
um
1.
2.
3.
4.
5.
19
20
37-Rubidium would have all of the
following characteristics except?
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
17
ro
n
al
1V
om
Ro
16
0%
Ele
ct
pe
r
Te
m
Br
Hi
gh
15
ur
e
at
ne
it t
le
le
ab
al
M
14
at
5
id
4
So
l
3
0%
en
ce
y
ilit
ity
uc
tiv
2
Hi
gh
Co
nd
Hi
gh
1
ss
1. High Conductivity
2. High Malleability
3. High Brittleness
4. Solid at Room Temperature
0% 0% 0%
5. 1 Valence Electron
18
19
20
35-Bromine would have which one of
the following characteristics?
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
17
s
ro
n
ct
en
ce
al
om
Ro
16
0%
Ele
pe
r
Te
m
Br
Hi
gh
15
ur
e
at
ne
it t
le
le
ab
al
M
14
at
5
id
4
So
l
3
0%
7V
y
ilit
ity
uc
tiv
2
Hi
gh
Co
nd
Hi
gh
1
ss
1. High Conductivity
2. High Malleability
3. High Brittleness
4. Solid at Room Temperature
0% 0% 0%
5. 7 Valence Electrons
18
19
20
```