Required Reading

Nelson Biology 12: Chapter 1.1 (p.12-16)

The Need To Be Full

"A full belly - I mean orbital - is a happy belly - I mean orbital." - Ms. dela Paz

In the last lesson, we reviewed the structure of the atoms of different elements. In this section, we will look at what happens when atoms get together.

Each atom has electrons that float around in orbitals around the nucleus. The outermost orbital, or energy shell, is called the valence shell, and it is the happiest, or most stable, when it is full of electrons.

Filling an orbital with electrons creates a stable situation, and atoms with incomplete orbitals will attach themselves to other atoms in order to fill those outermost energy shells. This is the basis of chemical reactions. When atoms of chemically reactive elements combine, they form compounds.

Atoms of chemically reactive elements form a stable attraction called a chemical bond.

Let's do a quick review of how chemical bonds are formed. The following TED-Ed video has a great summary of chemical bonding:

So what are the takeaways from this video? (Fill in the blanks and add to your ePortfolio)

Ionic bonds form when one metal atom ________________ electrons to a "hungry" non-metal atom.
Covalent bonds form when two atoms _______________ the electrons in their valence shell.

Pro Tip:

the number of lone electrons in a valence shell of an atom = the number of bonds it can make with other atoms

Let's practice how this works with the following activity.

ePortfolio Submission: Polarity and Intermolecular Forces Gizmo

Don't remember how chemical bonding works or what the difference is between ionic and covalent bonds? Don't worry - you can remind yourself with the following activity. Complete the worksheets and submit your work as part of your ePortfolio. Use these as notes for this part of the lesson.

Steps:

1. Download the worksheet here: AAO Polarity and Intermolecular Gizmo WS.pdf

2. Log into your account at www.explorelearning.com.

4. Once you get into the Biology classroom, scroll down to the SBI4U Gizmos and select the Polarity and Intermolecular Forces Gizmo.

5. Complete the worksheets using the Polarity and Intermolecular Forces Gizmo. Scan your written worksheets and submit to your ePortfolio.

6. Complete the online assessment questions that are found just beneath the Gizmo simulation (scroll down on the page).