1. Bohr Diagram, Electron configurations, and charges

2. First the rules Atomic number = the number of protons
Atomic mass = the number of protons and neutrons
Periods are rows and run left to right
Groups are columns and run top to bottom
Shells:
1st: holds only 2 electrons (relates to the first period)
2nd: holds only 8 electrons (relates to the second period)
3rd: holds only 8 electrons (relates to the third period)

3. First the rules
Groups are columns and run up and down, they increase by one going left to right
Group 1
Group 18/8A
Group 2
Group 13/3A
Group 14/4A
Group 15/5A
Group 16/6A
Group 17/7A

4. First the rules
Periods are the rows and run left to right, they increase by one going from up to down
PERIOD 1
PERIOD 2
PERIOD 3
PERIOD 4

5. First the rules OUTSIDE THE NUCLEUS Electrons (e-): INSIDE THE NUCLEUS
(-) negatively charged
Located outside the nucleus
No mass
INSIDE THE NUCLEUS
Protons:
(+) positively charged
Located in the nucleus
1 amu
Neutron:
No charge

6. Bohr diagrams and explanations
Hydrogen
Remember the rules:
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus

7. Bohr diagrams and explanations
HELIUM
Remember the rules:
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus

8. Bohr diagrams and explanations
Remember the rules:
LITHIUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Round up to an atomic mass of 7
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL

9. Bohr diagrams and explanations
Remember the rules:
BERYLLIUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Be” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “Be” is in GROUP 2 = 2 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

10. Bohr diagrams and explanations
Remember the rules:
BORON
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “B” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “B” is in GROUP 3A = 3 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

11. Bohr diagrams and explanations
Remember the rules:
CARBON
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “C” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “C” is in GROUP 4A = 4 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

12. Bohr diagrams and explanations
Remember the rules:
NITROGEN
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “N” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “N” is in GROUP 5A = 5 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

13. Bohr diagrams and explanations
Remember the rules:
OXGYEN
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “O” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “O” is in GROUP 6A = 6 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

14. Bohr diagrams and explanations
FLOURINE
Remember the rules:
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “F” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “F” is in GROUP 7A = 7 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

15. Bohr diagrams and explanations
Remember the rules:
NEON
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Ne” is in PERIOD 2 = draw two shells (first shell holds 2 electrons)
Hint: “Ne” is in GROUP 8A = 8 electrons are on the second shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

16. Bohr diagrams and explanations
Remember the rules:
SODIUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Na” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “Na” is in GROUP 1 = 1 electron on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

17. Bohr diagrams and explanations
Remember the rules:
MAGNESIUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Mg” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “Mg” is in GROUP 2 = 2 electron on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

18. Bohr diagrams and explanations
Remember the rules:
ALUMINUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Al” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “Al” is in GROUP 3A/13 = 3 electrons on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

19. Bohr diagrams and explanations
Remember the rules:
SILICON
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Si” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “Si” is in GROUP 4A/14 = 4 electrons on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

20. Bohr diagrams and explanations
Remember the rules:
PHOSPHORUS
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “P” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “P” is in GROUP 5A/15 = 2 electrons on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

21. Bohr diagrams and explanations
Remember the rules:
SULFUR
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “S” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “S” is in GROUP 6A/16 = 6 electrons on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

22. Bohr diagrams and explanations
Remember the rules:
CHLORINE
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Cl” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “Cl” is in GROUP 7A/17 = 7 electrons on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

23. Bohr diagrams and explanations
Remember the rules:
ARGON
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Ar” is in PERIOD 3 = draw three shells (first shell holds 2 electrons, second shell holds 8)
Hint: “Ar” is in GROUP 8A/18 = 8 electrons on the third shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

24. Bohr diagrams and explanations
Remember the rules:
POTASSIUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, 8 IN THE THIRD SO WE HAVE TO ADD ANOTHER SHELL
Hint: “K” is in PERIOD 4 = draw three shells (first shell holds 2 electrons, second shell holds 8, the third also holds 8)
Hint: “K” is in GROUP 1= 1 electron on the fourth shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number

25. Bohr diagrams and explanations
Remember the rules:
CALCIUM
Atomic number= # of Protons
Atomic mass = # protons + # neutrons
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus
ONLY 2 ELECTONS CAN GO IN THE FIRST SHELL, 8 IN THE SECOND, 8 IN THE THIRD SO WE HAVE TO ADD ANOTHER SHELL
Hint: “Ca” is in PERIOD 4 = draw three shells (first shell holds 2 electrons, second shell holds 8, the third also holds 8)
Hint: “Ca” is in GROUP 2 = 2 electrons on the fourth shell
Hint: Adding all the electrons should be equal to the number of protons and the atomic number