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!