Update: You will be taking a quiz either December 15 or 16 (you choose) over Section 2.1. It will be 7 MC and 3 short answer.
This week, we will cover Section 2.1; p. 57-68. Each subtopic has its own mission below.
I strongly suggest you outline Chapter 2 (and 3). It will be helpful for you to see the big picture in terms of what is expected for you to know.
1. Work your way through Section 2.1 by completing the missions. I will be providing supplemental material and am available to answer questions.
1. Describe the structure of the atom.
2. Determine the relative atomic mass from mass spectrum data.
Atomic Theory Structure
Mission 1: Subatomic Particle Basics. All neutral atoms contain the same number of protons & electrons. The number of protons determines the element's identity. For instance, 8 protons = oxygen. 17 protons = chlorine. 20 protons = calcium. This does not change.
Electrons determine chemical behavior. Valence electrons (electrons in the outermost energy levels) are significant in this regard, because the number of valence electrons determine how an element behaves in certain conditions. Elements with an octet (8 valence electrons) are unusually stable and do not combine to form compounds (noble gases have an octet, with the exception of helium).
Neutrons determine isotopes. They do not affect the charge or the element's identity. However, they do affect the mass of the nucleus. Several elements have multiple isotopes.
This is basic structural information about the atom; what we know for sure. We also suspect something else: that subatomic particles are made up of quarks and all particles have anti-particles that, when they collide, release energy in the form of gamma rays.
Mission 3: Subatomic Shenanigans. Isotopes are atoms with differing numbers of neutrons. Adding neutrons does not affect the element identity, but it does affect the element's mass. Almost every element has isotopes, and what is represented on the periodic table is an average of all of the isotopes of a particular element (which is why the atomic mass is a decimal). In Mission 5, you will learn how to use mass spectrum data to calculate relative atomic mass (RAM).
Ions are atoms with electrons removed or added, which leads to a lack of neutrality within the atom. There are two kinds of ions: positive, called cations, and negative, called anions. When electrons are stripped from an atom, the ion ends up with a positive charge because there are more protons than there are electrons. When electrons are added, the ion ends up with a negative charge because there are more electrons than protons. Typically metals are cations and nonmetals are anions. We will return to this mission at a later time, but it bears introducing now.
Mission 4: Back That Mass Up! A mass spectrometer can be used to measure the mass of individual atoms. Because the mass of an atom is ridiculously small (duh!), we use relative values according to an agreed-upon standard. Carbon-12 is the standard by which all atoms are measured (so I'm sure you can imagine that makes carbon a snarky element who doesn't get invited to the good parties).
When mass spec data is produced in the form of a mass spectrum. The X-axis shows the mass/charge ratio of the different ions on the C-12 scale, which is considered almost equal to their mass. The Y-axis shows the percent abundance of the ions.