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Key Concept Definitions and facts Examples

The lowest energy and most stable state of an atom.
Electrons are in order from lowest to highest shell.
Ground state electron configurations are given on the
Periodic Table.
For sodium (Na): 2 – 8 – 1

The high energy and unstable state of an atom.
Electrons are not in order.
Excited state electron configuration of an atom is
different from what is given on the Periodic Table.
For sodium (Na): 2 – 7 – 2 (may vary, but the
total e- must be 11)
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An electron can move from one shell to another
depending if energy is absorbed or released.

From low (ground) state to high (excited) state:
nd
2 rd The electron absorbs energy
From high (excited) state to low (ground) state:
rd
3 nd The electron releases energy

Band of colors produced when an excited electron
releases energy as it returns from a high to low state.

(Bright-line Spectrum) The electron transition from 3rd shell nd shell
will produce bright-line spectrum.

Shows line of colors produced at specific wavelengths
Pattern of colors is unique for each element, and can
be for identification.
wavelength (nm)
I I I I I I

H

Li
Na

Unknown
The unknown sample contains H and Na.

A lab procedure in which compounds of metallic ions
are heated to produce unique flame colors (light energy).
It can be used to make a rough identification of the
metallic ion that is present in a sample.

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