How to draw bohr diagrams (slideshare)

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Transcript of How to draw bohr diagrams (slideshare)

  • 1. How to DrawBohr Diagrams

2. Atomic Structure Atoms have a nucleus that contains Protonsand Neutrons Electrons are contained in shells thatsurround the nucleus An atom is made of mostly empty space Protons have a positive (+) charge Electrons have a negative (-) charge Neutrons are Neutral 3. Valence Electrons Each electron shell can hold Electron Number ofa certain number ofShellElectronselectrons Electron shells are filled 12from the inside out28 Noble Gases have full outer 38electron shells All other elements have418partially filled outer 518electron shells 632 732 4. Valence Electrons The electrons in the outer most electron shellare called valence electrons The shell containing electrons that is furthestfrom the nucleus is called the valence shell The number of electron shells with electronsis the same as (=) the period number Atoms will try to gain or lose electrons to havea full valence shell 5. Bohr Diagrams1) Find your element on the periodic table.2) Determine the number of electrons it is the same as the atomic number.3) This is how many electrons you will draw. 6. Bohr Diagrams Find out which period(row) your element is in. Elements in the 1stperiod have one energylevel. Elements in the 2ndperiod have two energylevels, and so on. 7. Bohr Diagrams 1) Draw a nucleus withthe element symbolinside. 2) Carbon is in the 2ndC period, so it has twoenergy levels, or shells. 3) Draw the shells aroundthe nucleus. 8. Bohr Diagrams1) Add the electrons.2) Carbon has 6 electrons.C 3) The first shell can only hold 2 electrons. 9. Bohr Diagrams1) Since you have 2 electrons already drawn, you need to add 4 more.C 2) These go in the 2nd shell.3) Add one at a time -starting on the right side and going counter clock-wise. 10. Bohr Diagrams Check your work. You should have 6 totalelectrons for Carbon. Only two electrons canCfit in the 1st shell. The 2nd shell can hold upto 8 electrons. The 3rd shell can hold 18,but the elements in thefirst few periods onlyuse 8 electrons. 11. Bohr DiagramsEnd of Study Guide.You should know how to draw a Bohr Diagram forthe first 20 elements.