atoms electron microscope image and electrons atoms and molecules in inorganic chemistry
Dr.SamuelHunt,United Arab Emirates,Teacher
Electrons in Atoms
Periodic TableClassical View of the Universe
• Since the time of the ancient Greeks, the stuff of the physical
universe has been classified as either matter or energy.
• Matter is has to have mass and volume
• Energy, is not composed of particles.
• Energy can only travel in waves.
www.ThesisScientist.comThe Nature of Light—Its Wave
• Light is a form of electromagnetic
• Electromagnetic radiation is made of waves
called photons; traveling at ―c‖
• Electromagnetic radiation moves through
space like waves move across the surface of a
www.ThesisScientist.comSpeed of Energy Transmission
• Every wave has four characteristics that
determine its properties:
number of wave peaks that pass in a given time.
• All electromagnetic waves move through
space at the same, constant speed.
3.00 x 10 meters per second in a vacuum = The
speed of light, c.
• The amplitude is the height of the wave.
The distance from node to crest.
The amplitude is a measure of how intense the light is—the
larger the amplitude, the brighter the light.
• The wavelength (l) is a measure of the distance
covered by the wave.
The distance from one crest to the next.
Or the distance from one trough to the next, or the distance between
It is actually one full cycle, 2π
Usually measured in nanometers.
1 nm = 1 x 10 m
• The frequency (n) is the number of waves that
pass a point in a given period of time.
The number of waves = number of cycles.
Units are hertz (Hz), or cycles/s = s .
1 Hz = 1 s
• The total energy is proportional to the amplitude
and frequency of the waves.
The larger the wave amplitude, the more force it has.
The more frequently the waves strike, the more total
force there is.
www.ThesisScientist.comLow Frequency Wave
High Frequency Wave
www.ThesisScientist.comThe Electromagnetic Spectrum
• Light passed through a prism is separated into all its
colors. This is called a continuous spectrum.
• The color of the light is determined by its wavelength.
• The color of light is determined by its wavelength.
• White light is a mixture of all the colors of visible light.
• When an object absorbs some of the wavelengths of
white light while reflecting others, it appears colored.
The observed color is predominantly the colors reflected.
Called transmitted light
www.ThesisScientist.comTypes of Electromagnetic Radiation
• Classified by the Wavelength
Radiowaves = l 0.01 m.
Low frequency and energy.
Microwaves = 10 m l 10 m.
Infrared (IR) = 8 x 10 l 10 m.
Visible = 4 x 10 l 8 x 10 m.
Ultraviolet (UV) = 10 l 4 x 10 m.
X-rays = 10 l 10 m.
Gamma rays = l 10 .
High frequency and energy.
www.ThesisScientist.comParticles of Light
• Scientists in the early 20 century showed that
electromagnetic radiation was composed of
particles we call photons.
Max Planck and Albert Einstein.
Photons are particles of light energy.
• One wavelength of light has photons with that
amount of energy.
www.ThesisScientist.comThe Electromagnetic Spectrum and
• Short wavelength light have photons with
highest energy = High frequency
Radio wave photons have the lowest energy.
Gamma ray photons have the highest energy.
• High-energy electromagnetic radiation can
potentially damage biological molecules.
The waves fit between atom-atom bonds, and
vibrate/shake the atoms loose
www.ThesisScientist.comOrder the Following Types of
Microwaves, Gamma Rays, Green Light, Red
Light, Ultraviolet Light, Continued
• By wavelength (short to long).
Gamma UV green red microwaves.
• By frequency (low to high).
Microwaves red green UV gamma.
• By energy (least to most).
Microwaves red green UV gamma.
www.ThesisScientist.comLight’s Relationship to Matter
• Single atoms can acquire extra
energy/photons, and then they release
• When atoms emit back energy, it
usually is released in the form of
• However, atoms don’t emit all colors,
only very specific wavelengths.
In fact, the spectrum of wavelengths can
be used to identify the element.
www.ThesisScientist.comAbsorption spectrum Emission spectrum
656.3 486.1 434.1 410.2