The Physical Setting

1
The Physical Setting

• Chemistry

2
The electron configuration for the ground state
of an atom is given on the Periodic Table of the
Elements.
Electron Configuration
3
Regents Question 06/02 1

• What is the electron configuration of a sulfur
  atom in the ground state?
• 2-4
• 2-6
• 2-8-4
• 2-8-6

þ
Look at the Periodic Table of the Elements
4
When an electron in an atom gains a specific
amount of energy, the electron is at a higher
energy state call the excited state.
Possible excited states for Na are 2-7-2 1-8-2
5
Regents Question 06/03 51-52

• Base your answers to the next two questions on
  the electron configuration table shown below.
• What is the total number of valence electrons in
  an atom of electron configuration X?
• Which electron configuration represents the
  excited state of a calcium atom?
• Element Electron
  
  Configuration
• X 2 8 8 2 Y 2 8 7
  3 Z 2 8 8

2
2-8-7-3
6
When an electron returns from a higher energy
state to a lower energy state, a specific amount
of energy is emitted call a quantum.
(plural-quanta)This quantum is part of the
electromagnetic spectrum.
7
The Visible Spectrum  Typically, superheated
solids and liquids will emit light of all
colors.  We see it as white light but if we use
a spectroscope or prism to separate the light by
different frequencies, we see it as a spectrum
like the one above.
8
The Emission Spectrum  When an excited atom,
falls back it gives off a unique absorption
spectrum.
This emitted energy can be used to identify an
element by using a chart of know values
Emission Spectrum
9
(No Transcript)
10
Regents Question 01/03 2

• During a flame test, ions of a specific metal are
  heated in the flam of a gas burner. A
  characteristic color of light was emitted by
  these ions in the flame when the electrons
• Gain energy as they return to lower energy levels
• Gain energy as they move to higher energy levels
• Emit energy as they return to lower energy levels
• Emit energy as they move to higher energy levels

þ
11
Regents Question 06/03 3

• When the electrons of an excited atom return to a
  lower energy state, the energy emitted can result
  in the production of
• alpha particles
• (2) Isotopes
• (3) protons
• (4) spectra

þ
12
The outermost electrons in an atom are called the
valence electrons. In general, the number of
valence electrons affects the chemical properties
of an element.

• The ground state for Na is 2-8-1
• The valence shell is the third shell.
• The valence shell contains 1 electron.

13
Regents Question 08/02 2

• What is the total number of electrons in the
• valence shell of an atom of aluminum in the
• ground state?
• 8
• 2
• 3
• (4) 10

þ
14
Regents Question 06/02 31

• In which shell are the valence electrons of the
  elements in Period 2 found?
• 1
• 2
• 3
• 4

þ