Hugo Ortiz MorenoEscuela de Ingeniería

Universidad del Valle de México

Key words

Outcome:

1. You will remember the definition and objective of chemistry.

2. You will be able to describe the evolution of the atomic models.

3. You will be able to develop the electronic configuration of any element.

4. You will be able to predict the behavior of an atom by its position in the periodic table.

Element

Atomic model

Bohr

Electron

Paired electrons

Unpaired electrons

Quantum

Quantum numbers

n, l, m, s values.

Electronic configuration

Period

Periodic table

Periodic properties (electronegativity, ionization potential, electronic affinity)

Group 1. Alkaline metals

Group 2. Earth alkaline metals

Li = LithiumNa = SodiumK = PotassiumRb = RubidiumCs = CesiumFr = FranciumVery electropositive and reactive elements. They usually form positive ions.

Be = BerylliumMg = Magnesium Ca = CalciumSr = StrontiumBa = BariumRa = RadiumLess electropositive than alkaline elements but they are very reactive too.

Group 3 - 12. Transition metals

Group 17. The halogen elements

Almost all of their compounds are colored and they are very useful in our daily life.Guess where and how!

Very reactive and electronegative elements. They usually form negative ions.

Metals Nonmetals

One hybrid classification. Metalloid

Metalloids are some of the elements that have best contributed to modern technologies development.

Guess where and how!

Group 18. Noble gases

Very stable gases.

Guess why!

Lanthanides and Actinides

Lanthanides are named rare earth elements too.The actinides group is constituted by radioactive elements with atomic numbers 89 through 103. It was first suggested by Glenn Seaborg.

Give the name, the atomic number and the electronic configuration of the external shell of the most electropositive elements.

Give the name, the atomic number and the electronic configuration of the external shell of the most electronegative elements.

The periodic parameters

(Atomic mass, Atomic size, Electronegativity, Electron affinity and Ionization Potential)

• Atomic mass: The mass of an isotope of a given element.

• Atomic size: The size of an element usually given as a radii.

• Electronegativity: the tendency of an atom or radical to attract electrons in the formation of a bond.

• Electron affinity: The ability of an element to accept an electron to form an ion.

• Ionization Potential: The minimum energy necessary to pick up an electron from a gas state atom in its basal state.

Atomic Sizes (in Angstroms, which is 10-10 meter) from Various Sources

1.58 0.3 1.2

0.98 n.a.

4.10 1.52

2.80 1.12

2.34 0.88

1.82 0.77

1.50 0.70 1.5

1.30 0.66 1.40

1.14 0.64 1.35

1.02 n.a. 1.60

4.46 1.86

3.44 1.60

3.64 1.43

2.92 1.17

2.46 1.10 1.9

2.18 1.04 1.85

1.94 0.99 1.80

1.76 n.a. 1.92

5.54 2.31

4.46 1.97

4.18 1.60

4.00 1.46

3.84 1.31

3.70 1.25

3.58 1.29

3.44 1.26

3.34 1.25

3.24 1.24

3.14 1.28

3.06 1.33

3.62 1.22

3.04 1.22

2.66 1.21 2.0

2.44 1.17 2.00

2.24 1.14 1.95

2.06 n.a. 1.97

5.96 2.44

4.90 2.15

4.54 1.80

4.32 1.57

4.16 1.41

4.02 1.36

3.90 1.3

3.78 1.33

3.66 1.34

3.58 1.38

3.50 1.44

3.42 1.49

4.00 1.62

3.44 1.4

3.06 1.41 2.2

2.84 1.37 2.20

2.64 1.33 2.15

2.48 n.a. 2.17

6.68 2.62

5.56 2.17

5.48 1.88

4.32 1.57

4.18 1.43

4.04 1.37

3.94 1.37

3.84 1.34

3.74 1.35

3.66 1.38

3.58 1.44

3.52 1.52

4.16 1.71

3.62 1.75

3.26 1.46

3.06 1.4

2.86 1.4

2.68 n.a.

2.7

2.20

2.2

Atomic diameter computed using quantum mechanical calculations, Periodic Chart of the Atoms (1979), Sargent-WelchAtomic radii and covalent radii, "Chemical Systems," Chemical Bond Approach Project (1964), McGraw-HillVan der Waals radii, Handbook of Chemistry and Physics, 65th Ed. (1984), CRC Press and "Chemical Systems"

Increases

Electronegativity in the periodic table

Activities

• Which element is the most electropositive; C, N, S, O.

• Which elements have no electronegativity defined; Cl, H, Kr, Xe, P.

• Write your own conclusions with a partner and share them with the class. (only 5 min)