Download 14.2 Notes on Electrons Atoms interact with each other through their

14.2 Notes on Electrons
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Atoms interact with each other through their electrons
Almost all properties of elements are due to electrons
Almost all light you see comes from atoms
Each different element has its own characteristic pattern of colors called a spectrum
The colors of everything around you come from this property of elements that allows them to
emit or absorb light of only certain colors
o Look at 14.11 p. 322 this is a diagram of a spectrum. The bright colored lines represent
light of different energies from an element.
Ex. Fireworks contain different elements in them for displaying different colors. The
different colors occur because atoms of various elements emit light at different frequencies.
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Each individual color in a spectrum is called a spectral line because each color appears as a line
in a spectroscope
o A spectroscope is a device that separates light into its different colors
o Ex. A group of students use a spectroscope to analyze three light sources. Different
bright, vertical lines appear as the light from each source enters the spectroscope. Each
light source shows a different spectral pattern because there are different elements in
each light source.
Atoms only emit certain colors of light therefore having certain values of energy
Niels Bohr came up with the concept of energy levels, his model helped scientists to understand
energy levels of atoms
o Electrons change energy levels by absorbing or emitting light
o An atom emits light when one of its electrons moves from a high energy level to a low
energy level
o An atom absorbs energy as its electrons move from a low energy level to a high energy
level
o Electrons with higher energy are located farther from the nucleus of the atom
o The first or lowest energy level can only hold 2 electrons, the 2nd and 3rd energy levels
can hold 8 electrons, and the 4th and 5th energy levels can hold 18 electrons; see p. 326