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Text Comments (25)

1 answer

Last reply by: Dr Carleen Eaton
Mon Feb 7, 2011 5:45 PM

Post by Jay Patel on February 1, 2011

Slight slip of the tongue at 3:50. She meant to say, this is two atoms of *hydrogen* bonded to one atom of water

0 answers

Post by Daniel Delaney on August 17, 2011

This takes a loooong time to download & google chrome doesn't help. Too bad because I like Dr. Eaton.

0 answers

Post by Raj Patel on November 21, 2011

buy, lots of stuff being covered in the first unit. still pretty understandable.

1 answer

Last reply by: Dr Carleen Eaton
Sat Feb 4, 2012 4:30 PM

Post by Jialan Wang on January 27, 2012

what is atr-x syndrome?
thanks!

1 answer

Last reply by: Dr Carleen Eaton
Thu Feb 23, 2012 11:36 AM

Post by Louise Finlayson on February 14, 2012

What a great lecture series - Thank you so much made things so much more understandable :)

0 answers

Post by nhuy nguyen on March 25, 2012

are we able to download the lecture? because I don't see where to download.

1 answer

Last reply by: Yejia Chen
Fri Apr 5, 2013 3:04 AM

Post by Swetha Atluri on June 3, 2012

In the Ionic Bonds section (32:35), how is the problem of the valence shells solved? It's solved in the Sodium, but it isn't solved in the Chlorine yet. After the electron from Sodium is transferred to Chlorine, there are only 8 electrons in the 3rd shell for Chlorine. Aren't there supposed to be 18 electrons in the third shell for it to have a full valence shell?

0 answers

Post by Andrea Gulyas on July 23, 2012

Thank you very much!
EI can hardly wait for the rest of the lectures!
:)

0 answers

Post by Bisrat Haile on August 9, 2012

can anybody help me please. I can't abel to see this lecture today. It says securty error: error #2048.

3 answers

Last reply by: stephen legge
Tue Mar 12, 2013 12:16 PM

Post by Aniket Dhawan on October 16, 2012

Professor is it possible that I could get a worksheet to do based on this lecture.

Otherwise you were very good.

Thanks

1 answer

Last reply by: Dr Carleen Eaton
Mon Nov 12, 2012 6:26 PM

Post by Lisa Lim on October 28, 2012

I don't understand the part where Dr. Eaton says, "the electron pretty much stays within these shells and they (electrons) only pass through them (?) on the way to a different shell." Who is "them"? I'm confused.

1 answer

Last reply by: Dr Carleen Eaton
Thu Dec 6, 2012 6:02 PM

Post by Jonathan Aguero on December 4, 2012

how is ionic bonding used in DNA

2 answers

Last reply by: Ikze Cho
Mon Mar 18, 2013 11:18 AM

Post by Ikze Cho on January 14 at 11:37:10 AM

is drinking pure H2O dangerous?

0 answers

Post by soe bryan on February 17 at 01:13:30 PM

what is an example of Van Der Waals forces?

Elements, Compounds, and Chemical Bonds

  • Elements are composed of atoms. Atoms are made up of protons, neutrons and electrons.
  • Electrons can be found at different energy levels. The particular energy levels that electrons spend most their time at are described as electron shells. The valence shell is the outermost electron shell in an atom.
  • Covalent bonds are formed when atoms share electron pairs.
  • Polar bonds are the result of an electron pair being more strongly attracted to one atom in the bond than another. Nonpolar bonds occur when an electron pair is equally attracted to both atoms forming the bond.
  • An ionic bond is the attraction between positively charged ions, called cations, and negatively charged ions, called anions.
  • A hydrogen bond is formed when a hydrogen atom covalently bound to one electronegative atom is also attracted to another electronegative atom.
  • Molecules undergo reactions by forming or breaking bonds. The initial substances involved in the reaction are called reactants; the set of substances resulting from the reaction are the products.
  • A mole (mol) = 6.02 x 1023. The molecular mass is the mass that contains one mol of the substance. The molarity of a solution is its concentration in moles of solute per liter of solution.

Elements, Compounds, and Chemical Bonds

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

AP Biology Intro