Section 2: Electrons in the Atom
Review (NOT ON NOTES) Atoms are the basic units of matter Nucleus (center of atom) made up of protons and neutrons with a cloud of electrons surrounding it
Electrons in an Atom In order to function properly, atoms must organize electrons so that they don’t collide. Electrons become organized into different energy levels. The outermost electrons in an atom are called the valence electrons.
Energy Levels Energy levels are located at set distances from the center of the atom Each energy level can contain a specific number of electrons: 1 st Energy Level – Closest to the nucleus; Can hold a maximum of 2 electrons 2 nd Energy Level and Beyond (3 rd, 4 th, etc.) – Each can hold a maximum of 8 valence electrons
Ground vs. Excited State The normal place where an electron would be is called its ground state. If the atom absorbs ENERGY (light, heat, etc.), electrons can JUMP UP an energy level. This would be its excited state. Electrons can not stay at this elevated position, so they fall back down to their original place When they fall back down, they GIVE OFF waves of energy!
Electromagnetic Spectrum Spectrum of energy with electric and magnetic properties Is comprised of… AC power Radio waves Microwaves Infrared radiation Visible light Ultraviolet radiation X-rays Gamma rays The lists above is in order of decreasing wavelength Smaller Wavelength = HIGHER energy
Wavelength The distance between similar parts of the curve (crest to crest; trough to trough)
Visible Light Part of the spectrum that we are able to see Made up of colors: ROYGBIV Red, orange, yellow, green, blue, indigo, violet Different colors come from different wavelengths Red has the longest wavelength and violet has the shortest wavelength
Light and the Structure of the Atom Each color in the visible light spectrum is a specific wavelength When electrons emit energy (fall from excited state back to ground state), they emit a color The color depends on the wavelength of energy being emitted
Atomic Spectrum Each element behaves in its own unique way when excited by heat/electricity, producing a very specific pattern of lines of color, called an atomic spectrum
NOW… Take a moment to summarize!