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Rhonda Alexander

Principle quantum numberDepends on energy leveln=(1,2,3, …)

Azimuthal quantum number

Shape of orbital-depends on location on periodic chart

If s block then l=0If p block then l=1If d block then l=2If f block then l=3

Atomic Orbitals1 – s

3 - p

5 – d

7 - f

Atomic Orbitals

d - orbitals

l ranges from 0 to n-1. If n=1, then l=0 If n=2 then l=0,1 If n=3 then l= 0, 1, 2

Angular Quantum Number

• ml represents the individual orbitals of a given type.

• ml ranges from –l to +l

• ml tells you which p, d, or f orbital the electron is in

Magnetic Quantum Number (ms): Spin

QuantumNumbers

Quantum Numbers

• n = integer from 1 to 7• l = 0 to n-1

• ml = -l to +l

• ms = 2

1or

2

1

HOW DO WE DESCRIBE THE LOCATION OF EACH ELECTRON IN AN ATOM?

WITH A SYMBOLIC NOTATION CALLED AN ELECTRON CONFIGURATION.

An Electron Configuration is a shorthand method of listing the location of the electrons in an atom. The system locates each electron by energy level and sublevel. The number of electrons in each sublevel is indicated with a superscript. For instance, the electronic configuration of Sodium is 1s22s22p63s1.This indicates that there are two electrons located in the 1s orbital, two electrons in the 2s orbital, six electrons in the 2p orbital and a single electron in the 3s orbital.

Remember:

ENERGY

LEVEL 1 2 3 4 SUBLEVELS s s p s p d s p d f

NUMBER OF

ORBITALS IN

SUBLEVELS

1 1 3 1 3 5 1 3 5 7

MAXIMUM

# OF e IN

SUBLEVELS

2 2 6 2 6 10 2 6 10 14

MAXIMUM

3 OF e IN

ENERGY LEVEL

2 8 18 32

Filling Orbitals

Follow rules of modern atomic model:Aufbau Principle -electrons fill from lowest energy level first

Hund’s Rule -have maximum number of unpaired electrons

Pauli Exclusion Theory -no electron has same set of quantum numbers because of electron spin

1.   Electrons occupy lowest energy orbitals first.

2.  An orbital can hold a maximum of 2 electrons. The Pauli Exclusion Principle must be obeyed.

3.   Hund's Rule must be obeyed; when placing electrons into degenerate orbitals, there must be one electron in each orbital before any pairing of electrons can take place. {Degenerate orbitals are orbitals of the same energy level and sublevel.}

RULES FOR PLACING ELECTRONS IN ORBITALSRULES FOR PLACING ELECTRONS IN ORBITALS

Aufbau Diagram

The Order Electrons Fill The Order Electrons Fill OrbitalsOrbitals

__ __ __ __ __ __ __ __ __ __ 5s 4d 5p 6s

__ __ __ __ __ __ __ __ __

1s 2s 2p 3s 3p__ __ __ __ __ __ __ __ __

4s 3d 4p

Electron Configuration of ZrElectron Configuration of Zr

1s2 2s2 2p63s2 3p6 4s2 3d10 4p6 5s2 4d2

Practice

• Write the electron configuration of the following on a separate page.– Oxygen– Lithium– Iron– Bromine– Tin

Core Notation of SnCore Notation of Sn• Locate Sn on the periodic table

Electron Configuration of SnElectron Configuration of SnSn [Kr]

• The noble gas core is Kr

Sn [Kr]5s2

• The noble gas core is Kr

• From Kr, go 2 spaces across the s-block in the 5th row 5s2

Sn [Kr]5s24d105p2

• The noble gas core is Kr

• From Kr, go 2 spaces across the s-block in the 5th row 5s2

• Then go 10 spaces across the d-block on the 5th row 4d10

• Finally go 2 spaces into the p-block on the 5th row 5p2

Steps

• Locate the element

• Go to the end of the row and up 1 noble gas

• Write the Noble gas core in brackets

• Continue electron configuration with the next period

• Refer to a periodic table and write the electron configurations of these atoms. Use the noble gas core.

• Zn

• I

Nobel Gas (Core) & Orbital DiagramNobel Gas (Core) & Orbital Diagram

[Ar]4s23d10

[Kr]5s24d105p5

4s 3d

5s 4d

5p

•Zn [Ar]4s23d10

•I [Kr]5s24d105p5

Quiz - Quantum Numbers

1. Zn

2. Sb

3. Cs

4. .n = 4.l = 3.ml = -3.ms = -1/2

.n = 3

.l = 2

.ml = +2

.ms = -1/2

.n = 5

.l = 1

.ml = +1

.ms = + 1/2.n = 6.l = 0.ml = 0.ms = +1/2

Tb

The Periodic Table

•Is a table that arranges the elements according to similarities in their properties.

Dmitri Mendeleev

Father of the Periodic Table

Mendeleev’s Periodic Table

(63 known elements)

Developed the Periodic Law that said: - columns arranged by increasing atomic mass (not correct) - rows arranged by chem. & physical properties

Mendeleev’s Table (cont.)

•Concluded gaps in table were elements yet to be discovered.

•- led to the search for missing elements

•- predicted existence of aluminum, boron, silicon, germanium

Predicted Properties Observed PropertiesAtomic weight 72 72.61Density 5.5 g/cm3 5.32 g/cm3

Melting point 825 C 938 COxide formula RO2 GeO2

Density of oxide 4.7 g/cm3 4.70 g/cm3

Chloride formula RCl4 GeCl4

Mendeleev’s Original Table

Modern Periodic Table- Developed by Henry Moseley

- Solved problems in Mendeleev’s table.- Periodic law is based on increasing

atomic #, NOT atomic mass.

Structure of the Periodic Table

periods: rows going across, numbered 1-7

groups: columns going down, numbered 1-18; aka families- Elements w/in groups have similar physical and chemical properties.

The Metals

•located left of zig-zag or stair-step

Properties - good conductors

- lusterous- malleable

- ductile

The Nonmetals

•located right of zig-zag or stair-step

•Properties:dull; brittle;

poor conductors,

The Metalloids

• Border zig-zag / stair-stepexcept aluminum and polonium

• Properties:- some metallic- some nonmetallic- semi-conductors

Transition Metals

Inner Transition Metals

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18IA IIA IIIA IVA VA VIA VIIA

VIIIA

Representative Elements

Transition Metals

Inner Transition Metals

Elements:

Alkali Metals

Halogens

Lanthanides

Metals Nonmetals Metalloids Transition Metals Inner Transition Groups/Families:

Alkali Earth Metals

Noble GasesActinides

nonmetalsmetals

Key Terms• Atomic radius – ½ distance btwn

nuclei of two atoms in a molecule.• Ionization energy – amt. of energy

needed to remove an e- from an atom.

• Electronegativity – tendency for an atom to attract e-

• Valence e- - e- on outermost energy level.

1 valence electron

2 valence electrons

3 valence electrons

4 valence electrons

5 valence electrons

6 valence electrons

7 valence electrons

8 valence electrons

Electrons in the outermost level are called valence electrons.

Element Families

Group 1) Alkali Metals (I A) - highly reactive, especially with water - 1 valence e-

- loses valence e-

- become 1+ ions

Li, Na, K, Rb, Cs, Fr

Group 2) Alkaline Earth Metals (II A)

- very reactive but less than group 1- 2 valence e-

- lose valence e-’s- become 2+ ions

Be, Mg, Ca, Sr, Ba, Ra

Groups 3-12) Transition Metals (B) - most have 2 valence e-, some with 1 or more - all lose valence e-

- several become 2+ ions

Sc Ti V Cr Mn

Fe Co Ni Cu Zn

Y Zr Nb Mo

Tc Ru Rh Pd Ag Cd

Lu Hf Ta W Re Os Ir Pt Au Hg

Lr Rf Db Sg Bh Hs Mt

3 4 5 6 7 8 9 10 11 12

Group 17) Halogens (VII A) - highly reactive - form cmpds called halides - fluorine most reactive element - 7 valence e-

- Gain 1 e-

- become 1- ions

F, Cl, Br, I, At

Group 18) Noble Gases (VIII A) - not reactive (inert) - cmpds formed only under special conditions - full outer energy level (8 valence e-) except He, 2 valence e-

He, Ne, Ar, Kr, Xe, Rn

Other Groups/Families

Group 13: 3 valence e- (IIIA) 14: 4 valence e- (IVA) 15: 5 valence e- (V A)

16: 6 valence e- (VI A)

Periodic TrendsAtomic Radius

INCREASEINCREASES

Atomic Radii

Ionization Energy

Periodic Trends

Ionization Energy

INCREASES

INCREASES

Ionization Energy

Periodic Trends

Electronegativity

O

M

I

T

INCREASES

INCREASES

Electronegativity

Ion Radius