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There are many exceptions to the octet rule that you should be aware of in chemistry. In this video we go through a list of exceptions with an explanation for each and examples. Knowledge of these octet exceptions is important for drawing Lewis Structures. When drawing Lewis dot Structures that involve elements which may be exceptions to the octet rule, you can calculate the formal charges to be sure you have the best/most likely Lewis Structure for the compound. More information: • How to Draw Lewis Structures: https://youtu.be/1ZlnzyHahvo • Formal Charges: https://youtu.be/vOFAPlq4y_k • Finding Valence Electrons (molecule): https://youtu.be/VBp7mKdcrDk • Duet Rule: https://youtu.be/R7SToNp1SO8 • My Chemical Bonding Webpage: www.thegeoexchange.org/chemistry/bonding Drawing/writing done in InkScape. Screen capture done with Camtasia Studio 4.0. Done on a Dell Dimension laptop computer with a Wacom digital tablet (Bamboo).
---- Balancing Chemical Equations in Five Easy Steps --- Balancing chemical equations is a core skill in chemistry. In this video you'll learn the basics for balancing equation with examples and explanation. Get more chemistry help at www.Breslyn.org. There are three key things to remember when balancing reactions. - First count the number of each type of atom on each side of the chemical equation. It helps to make a table below the equation to be sure you have the correct numbers. - You can only change the coefficients (these are the numbers in front substances). - You should NOT change the subscripts (the small numbers after elements). That would make a new chemical compound! Once you're done balancing a chemical equation double check both sides to be sure you have the same number of each type of atom on each side of the balanced equation. --- Drawing done captured with Camtasia Studio. Audio recording using a Yeti Blue microphone.
An explanation of how to find the number of valence electrons for molecules. This includes finding the number of valence electrons for negative and positive ions as well.
In this video we'll balance the equation BaCl2 + Al2(SO4)3 = BaSO4 + AlCl3 and provide the correct coefficients for each compound. To balance BaCl2 + Al2(SO4)3 = BaSO4 + AlCl3 you'll need to be sure to count all of atoms on each side of the chemical equation. When we balance equations with polyatomic ions, like SO4 2- it is helpful to consider the SO4 as one item as long as there is a SO4 on both sides of the chemical equation. Once you know how many of each type of atom you have you can only change the coefficients (the numbers in front of atoms or compounds) to balance the equation. Important tips for balancing chemical equations: - Only change the numbers in front of compounds (the coefficients). - Never change the numbers after atoms (the subscripts). - The number of each atom on both sides of the equation must be the same for the equation to be balanced. For a complete tutorial on balancing all types of chemical equations, watch my video: https://www.youtube.com/watch?v=zmdxMlb88Fs Drawing/writing done in InkScape. Screen capture done with Camtasia Studio 4.0. Done on a Dell Dimension laptop computer with a Wacom digital tablet (Bamboo).
A quick explanation of the molecular geometry of H2O including a description of the H2O bond angles. Note. the precise bond angle is 104.5. Looking at the H2O Lewis structure we can see that there are two atoms attached to the central Oxygen (O) atom and that there are two pair of lone pair of electrons (on the central O). Based on VSEPR Theory (Valence Shell Electron Pair Repulsion Theory) the electron clouds and lone pair electron around the O will repel each other. As a result they will be pushed apart giving the H2O molecule a bent molecular geometry or shape. The H2O bond angle will be about 109.5 degrees since it has a bent molecular geometry. Get more chemistry help at http://www.thegeoexchange.org/chemistry/bonding/
A step-by-step explanation of how to draw the BaBr2 Lewis Dot Structure.
For BaBr2 we have an ionic compound and we need to take that into account when we draw the Lewis Structure. We’ll first draw the metal and put it in brackets with its charge on the outside (video: finding ionic charge: https://youtu.be/M22YQ1hHhEY).
Next, we'll draw the Lewis Structure for the Br- ion and add brackets. We put the two ions together to complete the Lewis structure for BaBr2. Note that BaBr2 is also called Barium bromide.
For a complete tutorial on drawing Lewis Structures, see my video: https://youtu.be/1ZlnzyHahvo
For more practice, see https://youtu.be/DQclmBeIKTc
To learn to find the valence electrons: https://youtu.be/VBp7mKdcrDk
Note that is it more common to draw Lewis Structures for covalent (molecular) compounds where valance electrons are shared. In the case of ionic compounds, where we have a metal bonded to a non-metal (or group of non-metals), the Lewis diagram represents a formula unit. Many of these formula units make up a crystal lattice. So when we talk about the structure for BaBr2 we think of it together with other BaBr2 formula units in a crystal (NaCl is a good example of this: https://en.wikipedia.org/wiki/Sodium_chloride).
Get more chemistry help at http://www.thegeoexchange.org/chemistry/bonding
Drawing/writing done in InkScape. Screen capture done with Camtasia Studio 4.0. Done on a Dell Dimension laptop computer with a Wacom digital tablet (Bamboo).