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ORGANIZATION OF THE PERIODIC TABLE

November 2nd, 3rd & 4th, 2009

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How is the periodic table arranged? Periodic table is arranged by increasing

atomic number How did they decide when to add a new row?

A new row is needed so that elements are arranged with repeating properties in each column The properties of the elements repeat

periodically Hence… the periodic table!

There are many different ways to organize the elements…

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Circular

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Long Form

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Spiral

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Pyramid

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Layers

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Which one do you like the best?

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Why so many versions?

Everybody sees their own pattern in the elements

What patterns did we see? Shells

Outer Electrons

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Groups and Families

The columns in the periodic table are called groups, or families.

Each group has the same number of outer shell electronsGroup 1: Alkali Metals

Group 2: Alkaline Earth Metals

Group 7: HalogensGroup 8: Noble Gases

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Valence Electrons

All elements in a group have the same number of outer shell, or valence electrons

Valence electrons determine how an element will behave and what it bonds with

How many valence electrons does each group

have?

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Typical Charge (Ion Formed)

You should remember that 8 is great! Elements will either gain or lose electrons to

try to have 8 Elements with 3 or less electrons will LOSE

electrons Becoming _____________

Elements with 4 or more will GAIN electrons Becoming _____________

For Hydrogen and Helium, 2 is good too! They can’t possibly hold 8 electrons, so they

are full at 2

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Label:•Group name or number•# of valence electrons•Typical Charge

Practice

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Where are the electrons?-The Bohr Atom

Problems with Bohr Model Only worked for

Hydrogen Couldn’t explain

where the electrons were in atoms that had more than one electron

What Bohr got right Energy Levels

KomperdaThe difference between continuous and quantized energy levels

How do we think energy levels work?

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Quantum Mechanical Model

1. Electrons do not follow definite paths like the planets

2. Electrons have a probability of being found in a cloud of negative charge around the nucleus. These clouds have specific shapes.

3. There are areas around the nucleus that correspond with certain energy levels (like the Bohr Model)

4. The areas around the nucleus where the electron probably is (energy levels) are called orbitals

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Orbitals

Do not have sharp edges We can never map exactly where an electron

is at any given moment All we know is the probability of an electron

being in a certain place You know I’m probably in this room all day, you just

don’t know if I’m at my desk or in the storeroom or walking around

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The s Orbital

KomperdaThe p orbitals (three of them)

The d orbitals (five of them)

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Relative size of the 1s, 2s, 3s orbitals

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Electron Filling

Electrons like to be close to the nucleus because that requires the least amount of energy

Electrons will fill the orbitals in this order: 1s orbital, then 2s, 2p, 3s, 3p, 4s, 3d, and so

on. This order can be seen just by looking at the

periodic table Larger numbers mean larger orbitals, which means

the electrons is farther away from the nucleus The farther away an electron is, the more energy it

has Think about where the office of a CEO is…

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Color in or outline the sections on your blank periodic table to match this diagram

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Electron Configuration

When we write out the location of all electrons in an atom, we are writing its electron configuration Think of it like a map

Fill in the missing information on your map Now locate the element with this electron

configuration 1s1

1s22s1

1s22s22p4

Write the electron configuration for Boron