Transcript Document 7237435

Why is the periodic table shaped like it is and how are
the elements arranged?
1
2
Elements are arranged according to atomic #
and e- configuration.
Li: 3 e-’s
1s2 2s1
Na: 11 e-’s 1s2 2s2 2p6 3s1
K: 19 e-’s
1s2 2s2 2p6 3s2 3p6 4s1
Paramagnetic or diamagnetic?
3
Valence orbitals: outer shell orbitals
beyond the closest noble-gas configuration
Valence electrons: “the ones that can
react” (located in the valence orbitals).
The other e-’s are called core electrons and don’t react.
2s2
3s2
4s2
5s2
6s2
7s2
2A
Be
Mg
Ca
Sr
Ba
Ra
Elements in a vertical row have the same
number of valence electrons.
4
2A
2
5
2s 2p
2 5
3s 3p
2 5
4s 4p
2 5
5s 5p
2 5
6s 6p
F
Cl
Br
I
At
5
6
Atomic size affects many properties, both physical and chemical
Atomic sizes:
7
8
Smaller
S
m
a
l
l
e
r
Li
Na
Be
B
C
N
O
F
WHY?
K
9
10
Ionization Energy:
The energy required to completely remove an
e- from an atom in its gaseous state.
Mg(g)  Mg1+ + eMg1+(g)  Mg2+ + e-
1st ionization energy
2nd ionization energy
Question: Which of the above ionizations would have the
highest ionization energy and why?
11
electron being lost:
1st
2nd
3rd
4th
5th
6th
7th
12
Increases
Increases
13
14
I.E. Overhead
15
Electron Affinites:
The energy change that occurs when an electron is
added to a gaseous atom .
Cl(g) + e-  Cl-(g) E = -349 kJ/mol
What does the negative value mean?
16
Electron affinity values
17
What is meant by metallic character?
18
Common Oxidation states: note the vertical similarities.
19
The Halogen Family:
Br2(l)
I2(s)
Cl2(g)
20
Alkali Metal Family
Li
Na
K
21