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Student Learning Map Left Side: LEQ2: How are atoms represented via Bohr Models?

Energy Levels and Bohr Diagrams

Energy Levels Energy levels are the possible energies and locations an electron in an atom can have. This is like the possible floors to rent a room in a hotel. Each level is a certain distance from the nucleus—the further you get from the nucleus (or ground floor), the greater the energy required and the greater the energy level. Each energy level is symbolized by “n” and a number.

Energy Level Diagrams The diagram below shows you all the possible energy levels and how they are labeled: Nucleus n = 1 n = 2 n = 3 n = 4 n = 5 n = 6 n = 7

Electrons and Energy Levels An electron’s energy level (and location) depends on how much energy the electron has. All electrons fill the lowest energy level first and will only fill a higher energy level if there is no more room in the one below it.

Maxing Out Energy Levels To know if an energy level is full, you must check the maximum number of electrons for each energy level. Energy LevelMaximum Number of Electrons

Drawing an Energy Level Diagram 1.Calculate how many protons (atomic number), how many electrons (protons – charge) and how many neutrons there are (mass # – atomic #). Example: Arsenic-75 Protons: 33 Electrons: 33 – 0 = 33 Neutrons: 75 – 33 = 42

Drawing an Energy Level Diagram 2.Draw the nucleus and write how many protons and how many neutrons are in the atom. Example: Arsenic p + means protons n means neutrons p + = 33 n = 42

Drawing an Energy Level Diagram 3.Add electrons to energy level n = 1. Stop when you run out of electrons OR when you fill the energy level, whichever happens first. Example: Arsenic Only 2 electrons of arsenic’s 33 total electrons can fit in energy level n = 1. p + = 33 n = 42

Drawing an Energy Level Diagram 4.If you still have more electrons in the atom, go to energy level n = 2. Continue to fill in your electrons until you run out of electrons OR when you fill the energy level, whichever happens first. Example: Arsenic Since only 2 electrons fit in n = 1, we must move to n = 2. Eight more fit here for a total of 10. p + = 33 n = 42

Drawing an Energy Level Diagram 5.If you still have more electrons, repeat step 4 for each energy level until you run out of electrons. Only draw the energy levels that have electrons in them. Example: Arsenic n = 1  2 e - n = 2  8 e - n = 3  18 e - n = 4  5 e - n = 5  0 e - n = 6  0 e - n = 7  0 e - Total = 33 e - p + = 33 n = 42

Calcium-42

Calcium-44 Isotopes are two atoms of the same element (aka same number of protons) that have a different number of neutrons (aka mass number). Draw the Bohr Energy Level Diagram for Calcium-44.

+3 Al 28 13

+2 Ba

Chlorine-40

Think about it... Why must the electrons be spaced as far apart as possible within each energy level? Which electron, one in n=3 or one in n=5 has more energy? Why is this true?

Find your Isotope Partner Each of you will make a poster on your specific isotope It must include the name of the isotope and a Bohr Model of the isotope including n levels Also must include the following table for your isotope Isotope Name Nuclear Symbol Atomic #Mass #ProtonsNeutronsElectrons