5 Steps to a 5 AP Chemistry 2019

(^68) › STEP 4. Review the Knowledge You Need to Score High
● Know how to set up problems using the factor label method.
● Know the differences between a solid, a liquid, and a gas at both the macroscopic and
microscopic levels.
● Know what part Dalton, Thompson, Millikan, and Rutherford had in the development
of the atomic model.
● Know the three basic subatomic particles—proton, neutron, and electron—their
symbols, mass in amu, and their location.
● Isotopes are atoms of the same element that have differing numbers of neutrons.
● Electrons are located in major energy levels called shells. Shells are divided into subshells,
and there are orbitals for each subshell.
● Know the electron capacity of each orbital (always 2).
● Be able to write both the energy-level diagram and the electronic configuration of an
atom or ion by applying both the Aufbau build-up principle and Hund’s rule.
● Know how the modern periodic table was developed, including the differences between
Mendeleev’s table and the current table.
● Periods are the horizontal rows on the periodic table; the elements have properties unlike
the other members of the period.
● Groups or families are the vertical rows on the periodic table; the elements have similar
properties.
● Know the properties of metals, nonmetals, and metalloids and which elements on the
periodic table belong to each group.
● Valence electrons are outer-shell electrons.
● The IA family is known as the alkali metals; the IIAs are the alkaline earth metals; the
VIIAs are the halogens; and the VIIIAs are the noble gases.
● Know why atoms get larger as we go from top to bottom in a group and slightly smaller
as we move from left to right on the periodic table. Remember that on the free-response
section, simply quoting a trend is not sufficient in answering the question. This is true
for all trends.
● Ionization energy is the energy it takes to remove an electron from a gaseous atom or ion.
It decreases from top to bottom and increases from left to right on the periodic table.
Much the same trend is noted for electron affinity, the energy change that takes place
when an electron is added to a gaseous atom or ion. The trends depend on the size of the
atom or ion and its effective nuclear charge.
● Oxidation numbers are bookkeeping numbers. Know the rules for assigning oxidation
numbers.
● Be able to name binary metal type and nonmetal type compounds, as well as ternary
compounds, oxyacids, simple coordination compounds, etc.