1 ELECTRON SHELL/BOHR DIAGRAMS ASSIGNMENT On a piece of paper, draw the Bohr diagrams for neutral atoms of each of the following elements: Chlorine Neon Fluorine Helium Aluminum Lithium Boron Argon Sodium Silicon Oxygen Magnesium For each diagram you construct, include the following information to compliment your diagrams: provide the element’s symbol inside give the atomic mass of an atom of the element indicate the number of protons and neutrons in the nucleus of the atom. To help with this, remember that atomic mass = protons + neutrons based on the diagram, would you expect this element to be reactive or nonreactive? Be sure to explain your answers 2 ANSWER KEY CHLORINE Atomic mass = 35.45 u Number of protons = 17 Cl Number of neutrons = 18 We can expect chlorine to be reactive because it is one electron away from filling it’s outer shell. Therefore, we can expect it to “seek” this electron from another atom, thereby making it reactive. FLUORINE Atomic mass = 19 u Number of protons = 9 F Number of neutrons = 10 We can expect fluorine to be reactive because it is one electron away from filling it’s outer shell. Therefore, we can expect it to “seek” this electron from another atom, thereby making it reactive. 3 ALUMINUM Atomic mass = 26.98 u Number of protons = 13 Al Number of neutrons = 14 We can expect aluminum to be reactive because it does not have a full outer shell of electrons. It has three it its outer shell which can be donated in a chemical reaction with another element. BORON Atomic mass = 10.81 u Number of protons = 5 B Number of neutrons = 6 We can expect boron to be reactive because, with 3 electrons in its outer shell, it is does not have a full, stable outer electron orbit. Therefore, we can expect it to donate these electrons to another atom in a chemical reaction. ***It should be noted that Boron, while reactive, is not as reactive as aluminum, which also have 3 electrons in its outer shell 4 LITHIUM Atomic mass = 6.939 u Number of protons = 3 Li Number of neutrons = 4 We can expect lithium to be reactive because it has just one electron in its outer shell. This electron can be donated in a reaction with another element. ARGON Atomic mass = 39.95 u Number of protons = 18 Ar Number of neutrons = 22 We can expect argon to be non-reactive. It has a full, stable outer shell of 8 electrons, meaning it is not in a position to donate or receive electrons, making it non-reactive. 5 SILICON Atomic mass = 28.09 u Number of protons = 14 Si Number of neutrons = 14 We can expect silicon to be reactive because, with 4 electrons in its outer shell, it does not have a full, stable outer shell of electrons. This makes it a candidate to donate or receive electrons in a reaction with another element. MAGNESIUM Atomic mass = 24.31 u Number of protons = 12 Mg Number of neutrons = 12 g We can expect magnesium to be reactive. It has only two electrons in its outer shell, forming an unstable situation where these electrons can be donated in a reaction with another element. 6 SODIUM Atomic mass = 22.99 u Number of protons = 11 Na Number of neutrons = 12 We can expect sodium to be reactive. It has only one electron in its outer shell, forming an unstable situation where this electron can be donated in a reaction with another element. OXYGEN Atomic mass = 16 u Number of protons = 8 O Number of neutrons = 8 We can expect oxygen to be reactive. The outer shell of oxygen contains six electrons, meaning it needs just two more electrons to make it’s outer shell full. Therefore, we can expect it to “seek” out these two electrons from another atom, thereby making it reactive. 7 NEON Atomic mass = 20.18 u Number of protons = 10 Ne Number of neutrons = 10 We can expect neon to be non-reactive. It has a full, stable outer shell of 8 electrons meaning it is not looking to donate or receive electrons, thereby making it non-reactive. HELIUM Atomic mass = 4.003 u Number of protons = 2 He He Number of neutrons = 2 Like neon above, we can expect helium to be non-reactive. It has a full, stable shell of 2 electrons meaning it is not looking to donate or receive electrons, thereby making it non-reactive.
