140 likes | 253 Views
Bell Ringer 11-4-10. Which question(s) did you find difficult on the test yesterday? Today you will write about one page of Cornell notes, then you will need a separate sheet of paper for an exit slip. What we’ve learned so far…. Atoms are made of protons, neutrons and electrons
E N D
Bell Ringer 11-4-10 • Which question(s) did you find difficult on the test yesterday? • Today you will write about one page of Cornell notes, then you will need a separate sheet of paper for an exit slip.
What we’ve learned so far… • Atoms are made of protons, neutrons and electrons • Protons determine the identity of the element • Neutrons determine the isotope • Protons and neutrons are located in the nucleus of the atom …but what about those electrons?
Electrons in the Atom November 4, 2010
Rutherford’s model of the atom: Discovered: • Atom is mostly empty space • Atom has a small, positively charged center (nucleus) • Problems: • How are electrons arranged? • Why don’t electrons crash into the nucleus?
Bohr Model • Electrons are arranged into specific orbitals around the nucleus • Electrons have different amounts of energy depending on the orbital they are in • Further away from nucleus = more energy • Closer to nucleus = less energy
Check for Understanding: In your notes: rank the following electrons from lowest energy to higher energy Energy increases as you move AWAY from the nucleus 1 4 4 3 1 2 3 2
Electrons can move! • Atoms can absorb energy or emit energy • Absorb energy electrons move to higher orbitals • Release energy electrons move to lower orbitals
Light • Energy absorbed/released by atoms can be in the form of light • Colors of light: ROY G. BIV • Red = lower energy • Violet = higher energy
How are atoms different? • Atoms of different elements have orbitals of different energies. • This means they can give off different colors of light! Atomic emission spectrum:the unique pattern of light emitted by a specific atom
Check for Understanding The atomic emission spectrum of an atom is given below. Identify which element it is in your notes using the known spectra below. Which element am I??? Helium Krypton Hydrogen Xenon
How do scientists know what stars are made of? • Stars are far away and extremely hot, so we can’t take direct samples of gas! • Scientists look at the light given off by the star Spectrum of light from the Sun neon helium hydrogen
Exit Slip For credit today, copy and complete the following questions on a separate sheet of paper using your notes: • Electrons are arranged in ____________ around the nucleus. • How does the energy of orbitals change as you move away from the nucleus? • Atoms _____________ energy when electrons move to higher orbitals. • Atoms _______________ energy when electrons move to lower orbitals • Purple light is __________________ in energy than red light. • What is an atomic emission spectrum?