Electron Orbitals and valance electrons Putting electrons in their proper energy level (orbital) Deciding how many electrons are in the outer most shell (valance)

Energy levels of electrons relate to the shells of an atom starting from the nucleus and working outward The shell closest to the nucleus contains electrons with the lowest energy levels In the shells going outward from the nucleus, electrons will have more energy. first shell (least energy level) Going away from the nucleus, the electrons in outer shells will have more energy. nucleus

Energy levels of an atom where electrons are found nucleus 1st shell (level/row) 2nd shell 3rd shell

Energy levels of electrons relate to rows on the periodic table Energy level 1 = the first row across on your periodic table (least amount of energy) Hydrogen and Helium only Energy level 2 = the second row across on your periodic table (gains in energy from first level) From Li to Ne Energy level 3 = the third row across on you periodic table. From Na to Ar The lowest energy level is closest to the nucleus which = 1 Then as they go out from the nucleus, the energy increases

1st row = 1st level Hydrogen and Helium are in the first row Hydrogen has 1 electron Helium has 2 electrons

Putting Electrons in orbitals Example Row 1 holds 2 electrons (row 1 is the first shell of an electron, e-) . If you see that there are 2 electrons in the inner most shell of an electron, then your have Helium. If you see that there is 1 electron in the inner most shell, you have Hydrogen.

Energy levels The order of the energy levels is as follows 2 electrons fit in Row 1 8 electrons fit in row 2 8 electrons fit in row 3 8 electrons fit in row 4 (skip all the middle elements (for our purposes) column 3B-12B When you get a shell filled with 8, put on another shell.

Distributing electrons Hydrogen is in row 1, column 1, and has 1 electron so Helium is in row 1 has 2 electrons so (Helium is an exception to the column 1 and 2, it should be in the second column, but isn’t because it is considered a noble gas because of its full shell).

Lithium has 3 protons, so 3 electrons to distribute though the energy levels This tells me that lithium is in the 2nd row and has 1 electron in that outer shell (level). (2nd row of the periodic table = 2nd shell (level). Beryllium has 4 protons, so 4 electrons to distribute through the energy shells (levels).

Boron has 5 electrons to distribute This tells me that boron is in the 2nd row with 3 electrons in its outer shell, 2 are in the first shell and 3 are in the second shell Notice that hydrogen is in the first column with 1 electron in its outer shell, lithium is in the first column with 1 electron in its outer shell, beryllium is in the second column with 2 electrons in its outer shell, and boron is in the third column with 3 electrons in its outer shell. See the pattern? Label your periodic table columns like that (1-8) skipping columns 3B-12B.

oxygen Oxygen is in the 6th column, so 6 electrons in its outer shell Can you put all of its electrons in their correct shells? Oxygen has 8 Protons, so 8 Electrons (how many protons an element has is the smaller number in its tile. The larger number is its mass number which is all its neutrons and protons added together) It has the same amount of Protons +charges as electrons -charges to make it neutral it wants to be neutral. It always works like this for our purposes.

Valance Shell The outer most shell that electrons are in is called its valance shell. In oxygen, the last row that you use while filling in electrons, is the second row. So, oxygen has 6 electrons in row two of the periodic table. It has 6 electrons in its outer most shell (valance shell).

Lewis Dot Oxygen Oxygen has 6 electrons in its outer most shell (shell 2/row 2) It has 6 electrons in its valance shell So, you write O for oxygen and put 6 dots around it. O Therefore, oxygen belongs in column 6 of the periodic table. How many dots would silicon have around it? Hint –it is in the third row and has 4 electrons in that row. Answer –it would have 4 dots around it and belongs in the 4th column Si

You try to distribute these atoms’ electrons and make a Lewis Dot picture of each Boron Nitrogen Oxygen

Neon Beryllium Magnesium

Potassium Phosphorus aluminum

Review and more Lithium Fluorine chlorine