A cation is...
"an ion with pawsitive charge," and,
"the cutest ion ever."

Week 9 Resources/ Assets
Updated October 28, 2018
Please make sure you READ everything on this page or you will miss important details. I will archive past weeks Announcements pages for a limited time only under the Trimester 1 tab, if you need to go back to a particular weeks information for any reason.

Week 8 Summary
On Tuesday, recollect that we started the class with the Candium lab; as theoretical chemists you had discovered a brand new element in the Candium family, along with three of its different isotopes (M&M's peanut, M&M's plain, and Skittles), and you were to perform various calculations on these isotopes after taking a piece count of each isotope and mass.  Hopefully, if you followed all the directions on the second page of the lab, you were able to determine percent abundance, relative abundance, average mass, and relative mass.
 
Started Chapter 6 - Chemical Names and Formulas
We have been studying atoms; but this week we begin a study of molecules: a molecule is made up of two or more atoms (atoms can be the same or different, such as O2, or CO). Compounds, on the other hand, are made up of two or more different atoms, such as NaCl, CO, or H2O. Oxygen gas (O2) is a molecule, but not a compound. Water (H2O) is a molecule and compound. Compounds can further be characterized as molecular or ionic.

Compounds are molecular if they:
  1. are composed of two or more different atoms;
  2. have relatively low melting and boiling points, with many existing as gases or liquids at room temperature
  3. are comprised of two or more nonmetals, such as CO, CO2, H2O, H2O2, and C2H6O (ethanol); and
  4. if bonds form between atoms due to the sharing of an electron pair.
By contrast, compounds are ionic if they
  1. are comprised of a metal and nonmetal;
  2. are comprised of ions - there is no equal sharing of a pair of electrons with these; and,
  3. are typically solid crystals at room temperature (unlike molecular compounds which are often liquids and gases); and,
  4. have very high melting points.
Once we have a good idea as to what characterizes compounds, we will need to abbreviate their names, by writing them as chemical formulas. Simply, it is cumbersome to always write "carbon dioxide," but easier to write CO2. Sodium chloride (table salt) can be abbreviated as NaCl. 

Monatomic cations and anions
We briefly discussed monatomic ions, which come in two varieties, (1) as positively-charged cations, or (2) negatively-charged anions. You should know, by looking at the periodic table, what kinds of ions certain atoms are destined to become.
  • Alkali metals in Column 1A, tend to lose a single electron, making these a cation with a single positive charge (Na+).
  • Alkaline earth metals (in Column 2A) tend to lose two electrons, making these a cation with a 2+ charge.
  • Halogens, which reside in Column 7A - such as fluorine, chlorine, bromine and iodine - tend to gain a single electron, making these an anion with a single negative charge.
When naming monatomic cations, we simply state the name of the atom from which it is derived, and add the work "ion," such as "sodium ion." By contrast, when naming monatomic anions, and -ide suffix is attached, and the name is changed; such as "bromide," or "chloride," or "oxide."

Polyatomic ions
I briefly mentioned polyatomic ions, which are clusters of atoms tightly held together acting as a unit, yet possessing a charge. You will need to memorize the structures and names of about 25 polyatomic ions - only because we will encounter these again and again throughout the rest of the year in chemistry. 
Upcoming Week 9
Please complete reading Chapter 6, and finish as many problems in the homework as you can - bringing any questions to class. I would like to finish Chapter 6 this week (if possible) and request that you turn in Test #2 the following Tuesday (November 6th).

Last Tuesday, I neglected to have you all take the Week 8 quiz, so be prepared this coming Tuesday to take this quiz along with the Week 9 quiz. I will also offer an extra credit quiz on the polyatomic ions. 
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So that you are adequately prepared for classes this coming week, please complete the following:
  1. Due in class: Candium Laboratory
  2. Be prepared to take the In-class Quiz #8.
  3. Be prepared to take the In-class Quiz #9.
  4. For extra credit prepare to take a quiz on polyatomic ions (no stress, it's extra credit!)
  5. Feel free to get ahead of Chapter 6 reading and homework problems (worksheets and Answer Key linked right).