Flame Test, Electron Configuration

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Flame Test, Electron Configuration
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Warm - Up

• What is a photon?
• How can we identify elements based on their
  emission spectrum?
• What is the Photoelectric Effect?
• Why do we say that light has a dual nature?

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Objective

• Today I will be able to
• Analyze the emission of energy in metals by
  completing a flame test
• Calculate the electron configuration for elements
  on the periodic table

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Homework

• Electron Configuration Practice

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Agenda

• Warm Up
• Flame Test Lab
• Electron Configuration Notes
• Electron Configuration Practice
• Exit Ticket

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Electron Configuration
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Electron Configuration

• Electron configuration arrangement of electrons
  in an atom
• Electrons try to populate the lowest energy
  levels available ground state

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Arrangement of Energy Levels

• Principal energy levels represented by n
• As atoms get bigger, there are more electrons,
  therefore more energy levels
• Within each energy level, we have one or more
  sublevels
• These sublevels are made up of orbitals

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Energy Levels on the Periodic Table
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Orbitals

• According to modern atomic theory electrons are
  found in orbitals
• Orbital 3-D region around the nucleus
  indicating the probable location of the electron
• There are 4 types of orbitals where the electrons
  can be found s,p,d,f
• Order of energy from lowest to highest
• s, p, d, f

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3-D images of the orbital's
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Energy Sublevels

• Each sublevel occupies a specific location on the
  periodic table

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Electron Configuration
n 1 2 3 4 5 6 7
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Arrangement of Energy Levels
n Sublevels
1 1s
2 2s, 2p
3 3s, 3p, 3d
4 4s, 4p, 4d, 4f
5 5s, 5p, 5d, 5f, 5g (rarely seen)
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Orbitals cont.

• Each sublevel can hold a specific amount of
  electrons
• S2
• P6
• D10
• F14

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Electron Configurations

• We can write the electron configurations for each
  element (assuming the atom has a neutral charge)
  representing the location of the elements
  electrons in the energy levels

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Examples

• Sodium (Na)
• Has 11 electrons (when neutral)
• Electron Configuration
• 1s22s22p63s1
• Cobalt (Co)
• Has 27 electrons (when neutral)
• Electron Configuration
• 1s22s22p63s23p64s23d7

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Why does 4s come before 3d?

• 3d is of slightly higher energy than 4s, but 4s
  is further from the nucleus

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z
y
The 3 axes represent 3-dimensional space
x
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z
y
The nucleus of the atom is at the center of the
three axes
x
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The 1s orbital is a sphere, centered around the
nucleus
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The 2s orbital is also a sphere
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The 2s electrons have a higher energy than the
1s electrons. Therefore, the 2s electrons are
generally more distant from the nucleus, making
the 2s orbital larger than the 1s orbital
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There are three 2p orbitals
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The three 2p orbitals are oriented perpendicular t
o each other
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z
This is one 2p orbital (2py)
y
x
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z
Another 2p orbital (2px)
y
x
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z
The third 2p orbital (2pz)
y
x
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z
2px
y
x
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z
2px and 2pz
y
x
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z
The three 2p orbitals, 2px, 2py, 2pz
y
x
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Once the 1s orbital is filled
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The 2s orbital begins to fill
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Once the 2s orbital is filled
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The 2p orbitals begin to fill
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Each 2p orbital intersects the 2s orbital and the
1s orbital
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Each 2p orbital gets one electron before pairing
begins
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Once each 2p orbital is filled with a pair of
electrons, then
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The 3s orbital gets the next two electrons
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The 3s electrons have a higher energy than 1s,
2s, or 2p electrons
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3s electrons are generally found further from
the nucleus than 1s, 2s, or 2p electrons
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Exit Ticket

• Explain the mechanism behind different colored
  fireworks