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Classic Chem

Classic Chem. Bonds – Valence Electrons and Atomic Structure. 9-12 Science Std: Chem 1d. What is a chemical bond?. It all has to do with electrostatic forces. A bond is:. The electrostatic attraction…. Between the nucleus of one atom. And the valence electrons of another atom.

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Classic Chem

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  1. Classic Chem Bonds – Valence Electrons and Atomic Structure 9-12 Science Std: Chem 1d

  2. What is a chemical bond? • It all has to do with electrostatic forces A bond is: The electrostatic attraction… Between the nucleus of one atom And the valence electrons of another atom

  3. Let’s review a couple of things • Inside the atom…. There is the nucleus The nucleus has protons and neutrons The protons have a positive electrical charge And the neutrons don’t have any electrical charge

  4. Let’s review a couple of things • So overall, the nucleus…. Has a positive electrical charge The electrons have a negative electrical charge So this holds the electrons in their orbitals

  5. Let’s review a couple of things • There are several layers of orbitals… And there are electrons in each layer So overall, The positive charge in the nucleus balances the negative charge of the electrons So the atom has a neutral charge

  6. But when 2 atoms get close… • Something else happens….. The negative electrons of one atom… Feel the positive nucleus of the other atom And the electrostatic forces hold them together

  7. But when 2 atoms get close… • It isn’t always a happy meeting…. The electrons on one atom like the nucleus But the electrons on that atom don’t like the electrons And they don’t want the other electrons near

  8. But when 2 atoms get close… • So when they do get close….. The electrons have to move around each other How they move around each other controls what kind of chemical bond is made

  9. Not all of the electrons care… • Remember the different orbital layers…. The electrons on the outside may see the other atom… But the electrons close in are happy with their own nucleus

  10. Not all of the electrons care… • So only the outer or valence electrons… Interact with the other atoms to make a chemical bond

  11. Reviewing the Valence Electrons • We look at the periodic table…

  12. How many valence electrons…. We will look at the main part of the table…. So you should know how many there are for any atom The number of valence electrons is important

  13. How many valence electrons…. Remember that the elements are arranged in periods…. # of valence electrons are the same in each group Properties repeat in each period

  14. How many valence electrons…. To find the number of valence electrons…. 1 2 3 4 5 6 7 8 #1: Count over from left to right You can do it 2 ways….

  15. How many valence electrons…. The number you count over from left to right…. 1 2 3 4 5 6 7 8 Is the number of valence electrons for that atom

  16. How many valence electrons…. But this starts to get a little confusing… 1 2 3 4 5 6 7 8 In the transition metals, it doesn’t work like that

  17. How many valence electrons…. The other way to do it may be easier…. You look at the group number above the chart.

  18. How many valence electrons…. The group number is….. The number of valence electrons for that atom!

  19. How many valence electrons…. The really nice thing about this… This even works in the transition metals Except for Group VIIIB which will be covered later….

  20. Why is this important…. The number of Valence Electrons determines whether or not an atom can bond This is the first step in finding what kind of chemical bond 2 elements will have

  21. To make sure you know… How many valence electrons are in each atom, Lets give you a chance to practice….

  22. To make sure you know… Take out your periodic tables and find the following information:

  23. Questions?

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