Periodic table Size of Atoms - Trends.ppt

Atomic size ppt

1. Atomic Radii
Li
Na
K
Rb
Cs
ClSPSiAl
BrSeAsGeGa
ITeSbSnIn
Tl Pb
Bi
Mg
Ca
Sr
Ba
Be FONCB
1.52 1.11
1.86 1.60
2.31 1.97
2.44 2.15
2.62 2.17
0.88 0.77 0.70 0.66 0.64
1.43 1.17 1.10 1.04 0.99
1.22 1.22 1.21 1.17 1.14
1.62 1.40 1.41 1.37 1.33
1.71 1.75 1.46
IA IIA IIIA IVA VA VIA VIIA
= 1 Angstrom

2. Li
Na
K
Rb
Cs
La
Xe
Kr
Zn
Cl
F
He
H
3d
transition
series
4d
transition
series
0.3
0.25
0.2
0.15
0.1
0.05
0
0 10 20 30 40 50 60
atomic number
a
t
o
m
ic

r
a
d
iu
s

3. Periodic Trends in Atomic Radii
LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 175

4. Relative Size of Atoms
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 350

5. Attraction and Repulsion of
Electrical Charges
++
Particles with opposite
charges attract
one another.
Particles with like charges
repel one another.
--+ -

6. Coulombic Attraction
1+ 1-
2+ 2-
4- 3-
2+ 2-
Coulombic Attraction
1) Charge
opposites attract
like repels
2) Distance
A
B
C
D

7. Shielding Effect
Kernel electrons block
the attractive force of
the nucleus from the
valence electrons
+
nucleus
Valence
Electrons
-
-
-
-
Electron
Shield
“kernel”
electrons

8. Shielding Effect and
Effective Nuclear Charge
+
__
_
Mg = [Ne]3s
2
attractions
repulsions
Hill, Petrucci, General Chemistry An Integrated Approach 2nd Edition, page 336
Mg
24.305
12

9. ++
+++
+
+
+
Decreasing Atomic Size
Across a Period
•As the attraction between the (+) nucleus and the (–) valence electrons , the
atomic size . Greater coulombic attraction.
•From left to right, size decreases because there is an increase in nuclear
charge and Effective Nuclear Charge (# protons – # core electrons).
•Each valence electron is pulled by the full ENC
(ENC = 1)
+
+
+
(ENC = 2)
+
Li Be
(ENC = 3)
B
1s
2
2s
1
1s
2
2s
2
1s
2
2s
2
2p
1
Li Be B

10. Sizes of ions: electron repulsion
•Valence electrons repel each other.
9 +
•When an atom becomes a
anion (adds an electron to its
valence shell) the repulsion
between valence electrons
increases without changing ENC
•Thus, F
–
is larger than F
Fluorine atom
F
1s
2
2s
2
2p
5
9+
-
-
-
-
-
-
-
-
-

F
1-
1s
2
2s
2
2p
6
+1e+1e
--
9+
-
-
-
-
-
-
-
-
-
-
Fluorine ionFluoride ion

11. Atomic Radius of Atoms
Na
K
Rb
Cs
ClSPSiAl
BrSeAsGeGa
ITeSbSnIn
TlPbBi
Mg
Ca
Sr
Ba
Be
FONCB

12. Atomic Radii
Li
Na
K
Rb
Cs
ClSPSiAl
BrSeAsGeGa
ITeSbSnIn
Tl Pb
Bi
Mg
Ca
Sr
Ba
Be FONCB
1.52 1.11
1.86 1.60
2.31 1.97
2.44 2.15
2.62 2.17
0.88 0.77 0.70 0.66 0.64
1.43 1.17 1.10 1.04 0.99
1.22 1.22 1.21 1.17 1.14
1.62 1.40 1.41 1.37 1.33
1.71 1.75 1.46
IA IIA IIIA IVA VA VIA VIIA
= 1 Angstrom
0.60 0.31
0.95 0.65
1.33 0.99
1.48 1.13
1.69 1.35
1.71 1.40 1.36
0.50 1.84 1.81
0.62 1.98 1.85
0.81 2.21 2.16
0.95
IA IIA IIIA IVA VA VIA VIIA
= 1 Angstrom
Li
1+
Be
2+
Na
1+
Mg
2+
Ba
2+
Sr
2+
Ca
2+K
1+
Rb
1+
Cs
1+
Cl
1-
N
3-
O
2- F
1-
S
2-
Se
2- Br
1-
Te
2- I
1-
Al
3+
Ga
3+
In
3+
Tl
3+
Ionic Radii

13. Atomic Radii
Li
Na
K
Rb
Cs
ClSPSiAl
BrSeAsGeGa
ITeSbSnIn
Tl Pb
Bi
Mg
Ca
Sr
Ba
Be FONCB
1.52 1.11
1.86 1.60
2.31 1.97
2.44 2.15
2.62 2.17
0.88 0.77 0.70 0.66 0.64
1.43 1.17 1.10 1.04 0.99
1.22 1.22 1.21 1.17 1.14
1.62 1.40 1.41 1.37 1.33
1.71 1.75 1.46
IA IIA IIIA IVA VA VIA VIIA
= 1 Angstrom
He
Ne
Ar
Kr
Xe
Rn
0.93
1.12
1.54
1.69
1.90
2.20
VIIIA

14. 0.60 0.31
0.95 0.65
1.33 0.99
1.48 1.13
1.69 1.35
1.71 1.40 1.36
0.50 1.84 1.81
0.62 1.98 1.85
0.81 2.21 2.16
0.95
IA IIA IIIA IVA VA VIA VIIA
= 1 Angstrom
Li
1+
Be
2+
Na
1+
Mg
2+
Ba
2+
Sr
2+
Ca
2+K
1+
Rb
1+
Cs
1+
Cl
1-
N
3-
O
2- F
1-
S
2-
Se
2- Br
1-
Te
2- I
1-
Al
3+
Ga
3+
In
3+
Tl
3+
Ionic Radii

15. Trends in Atomic and Ionic Size
152
186
227
Li
Na
K
60
Li
+
95
Na+
133
K+
e
e
e
F
-
136
Cl
-
181
Br
-
195
F
Cl
Br
64
99
114
e
e
e
Metals Nonmetals
Group 1
Al
143

50
e
e
e
Group 13 Group 17
Cations are smaller than parent atomsAnions are larger than parent atoms
Al
3+

16. 152
Li
60
Li
+
e
152

60
Li
+
e
e
e
e
Li
Lithium atom
Lithium ion
+
152
Li
Lithium atom
Li
E
n
e
r
g
y

17. IA IIA IIIA IVA VA VIA VIIA
0.60 0.31
0.95 0.65
1.33 0.99
1.48 1.13
1.69 1.35
1.71 1.40 1.36
0.50 1.84 1.81
0.62 1.98 1.85
0.81 2.21 2.16
0.95
Li
1+
Be
2+
Na
1+
Mg
2+






Cl
1-
N
3-
O
2-
F
1-
S
2-
Se
2-
Br
1-
Te
2-
I
1-
Al
3+
Ga
3+
In
3+
Tl
3+
Ca
2+
K
1+
Sr
2+
Rb
1+
Cs
1+
Ba
2+
Li
Na
K
Rb
Cs
ClSPSiAl
BrSeAsGeGa
ITeSbSn
In
Tl Pb Bi
Mg
Ca
Sr
Ba

1.52 1.11
1.86 1.60
2.31 1.97
2.44 2.15
2.62 2.17
0.88 0.77 0.70 0.66 0.64
1.43 1.17 1.10 1.04 0.99
1.22 1.22 1.21 1.17 1.14
1.62 1.40 1.41 1.37 1.33
1.71 1.75 1.46
Be B C N O F
= 1 Angstrom
Atomic
Radii
Ionic
Radii
Cations: smaller
than parent atoms
Anions: LARGER
than parent atoms

18. The Octet Rule and Common Ions
Oxygen atom
O
1s
2
2s
2
2p
4
Fluorine atom
F
1s
2
2s
2
2p
5
Sodium atom
Na
1s
2
2s
2
2p
6
3s
1
Magnesium atom
Mg
1s
2
2s
2
2p
6
3s
2
8+
-
-
-
-
-
-
-
-
9+
-
-
-
-
-
-
-
-
-
11+
-
-
-
-
-
-
-
-
-
-
-
12+
-
-
-
-
-
-
-
-
-
-
-
-
11+
-
-
-
-
-
-
-
-
-
-
12+
-
-
-
-
-
-
-
-
-
-
Oxygen ion
O
2-
1s
2
2s
2
2p
6
Fluorine ion
F
1-
1s
2
2s
2
2p
6
Sodium ion
Na
1+
1s
2
2s
2
2p
6

Magnesium ion
Mg
2+
1s
2
2s
2
2p
6
10+
-
-
-
-
-
-
-
-
-
-
Neon atom
Ne
1s
2
2s
2
2p
6
+1e+1e
--
-1e-1e
--
-2e-2e
--
+2e+2e
--
8+
-
-
-
-
-
-
-
-
-
-
9+
-
-
-
-
-
-
-
-
-
-

19. Isoelectronic Species
11+
-
-
-
-
-
-
-
-
-
-
12+
-
-
-
-
-
-
-
-
-
-
Oxygen ion
O
2-
1s
2
2s
2
2p
6
Fluorine ion
F
1-
1s
2
2s
2
2p
6
Sodium ion
Na
1+
1s
2
2s
2
2p
6

Magnesium ion
Mg
2+
1s
2
2s
2
2p
6
8+
-
-
-
-
-
-
-
-
-
-
9+
-
-
-
-
-
-
-
-
-
-
10+
-
-
-
-
-
-
-
-
-
-
Neon atom
Ne
1s
2
2s
2
2p
6
IsoelectronicIsoelectronic - all species have the same number of electrons.
Can you come up with another isoelectronic series of five elements?
p = 8
n = 8
e = 10
p = 9
n = 9
e = 10
p = 10
n = 10
e = 10
p = 11
n = 11
e = 10
p = 12
n = 12
e = 10

20. Lewis Structure
NaClX
oo
oo
o
oo
HCN
o
X
X
X
X





ClNa HCN
ClNa HCN
Gilbert Lewis
“Lewis Dot Notation”

21. Atomic Radius vs. Atomic Number
Li
Na
K
Rb
Cs
La
Xe
Kr
Zn
Cl
F
He
H
3d
transition
series
4d
transition
series
0.3
0.25
0.2
0.15
0.1
0.05
0
0 10 20 30 40 50 60
atomic number
a
t
o
m
ic

r
a
d
iu
s