AP Notes, Outlines, Study Guides, Vocabulary, Practice Exams and more!

Atoms and Chemical Bonds

atom - makes up all matter and all substances in the universe  

  • can be seen indirectly w/ tech such as tunnel microscopy
  • electrons - (-) charge; revolves around the nucleus
  • neutrons - no charge; in the nucleus
  • protons - (+) positive charge; in the nucleus; determines the atom's atomic number
  • mass - amount of substance
  • weight - force gravity exerts on a substance
  • atomic mass - equal the combined mass of neutrons/protons; measured in daltons (6.02*10^23 daltons=1 gram)

isotopes - atoms of an element w/ different numbers of neutrons  

  • elements - same atomic number, same chemical properties
  • radioactive isotope - isotopes that decay due to unstable nuclei; decay is constant
  • half-life - time is takes 1/2 of the atoms to decay; can be used to determine age of biological material
  • released subatomic particles could cause mutations in genes

electrons - determines the charge in each atom  

  • neutral atoms - not net charge, same number of electrons/protons
  • ions - atoms in which the number of electrons is different from the number of protons
  • cation - ion with positive charge
  • anion - ion with negative charge

orbital - area where an electron is most likely to be found  

  • each can't contain over 2 electrons
  • electrons determine the atom's chemical behavior because the nuclei never interact
  • electrons contain potential energy based on their position
  • oxidation - loss of electron
  • reduction - gain of electron
  • energy level - based on an electron's distance from the nucleus; different from orbitals

periodic table - developed by Dmitri Mendeleev  

  • elements' chemical properties repeated themselves in groups of 8
  • valence electrons - electrons on the outermost energy level; basis for the atoms' chemical properties
  • noble gases - elements w/ filled outer levels; are inert and nonreactive
  • halogens - elements w/ 7 electrons in outer levels; extremely reactive
  • octet rule - atoms tend to completely fill their outer levels

chemical bonds - connects atoms in a molecule and molecules in a compound  

  • ionic bonds - forms between atoms of opposite charge; exists between an ion and all oppositely charged ions in the area
  • covalent bonds - forms between 2 specific atoms when electrons are shared; has no net charge or free electrons
  • single bond - 1 electron is shared
  • double bond - 2 electrons are shared
  • triple bond - 3 electrons are shared
  • structural formulas - shows elements in a compound and their bonds
  • molecular formulas - shows only the elements in a compound
  • atoms can form many covalent bonds (ex. carbon)
  • chemical reaction - forming/breaking of chemical bonds
  • reactants - original molecules before the reaction
  • products - resulting molecules after the reaction

factors influencing reactions  

  • higher temperature increases reaction rate
  • temperature must not be so high that it destroys molecules
  • more reactants exposed to each other increases reaction rate
  • catalyst - substance that increases reaction rate; proteins called enzymes act as catalysts in organisms
Subject X2: 

Need Help?

We hope your visit has been a productive one. If you're having any problems, or would like to give some feedback, we'd love to hear from you.

For general help, questions, and suggestions, try our dedicated support forums.

If you need to contact the Course-Notes.Org web experience team, please use our contact form.

Need Notes?

While we strive to provide the most comprehensive notes for as many high school textbooks as possible, there are certainly going to be some that we miss. Drop us a note and let us know which textbooks you need. Be sure to include which edition of the textbook you are using! If we see enough demand, we'll do whatever we can to get those notes up on the site for you!