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Why is the periodic table shaped like it is and how are the elements arranged?

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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?

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Valence orbitals: outer shell orbitals beyond the closest noble-gas configuration

Valence electrons: “the ones that can react” (located in the valence orbitals).

Elements in a vertical row have the same number of valence electrons.

2ABeMgCaSrBaRa

2s2

3s2

4s2

5s2

6s2

7s2

The other e-’s are called core electrons and don’t react.

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2A

2s22p5 F3s23p5 Cl4s24p5 Br5s25p5 I6s26p5 At

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Atomic sizes:

Atomic size affects many properties, both physical and chemical

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Li Be B C N O F

Na

Smaller

Smaller

WHY?

K

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Ionization Energy:

The energy required to completely remove an e- from an atom in its gaseous state.

Mg(g) Mg1+ + e- 1st ionization energy

Mg1+(g) Mg2+ + e- 2nd ionization energy

Question: Which of the above ionizations would have the highest ionization energy and why?

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electron being lost: 1st 2nd 3rd 4th 5th 6th 7th

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Increases

Increases

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I.E. Overhead

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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?

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Electron affinity values

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What is meant by metallic character?

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Common Oxidation states: note the vertical similarities.

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I2(s)Cl2(g)

Br2(l)

The Halogen Family:

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Li KNa

Alkali Metal Family