CP Chemistry 420
October
UNIT 2A: ORGANIZATION OF MATTER (THE ATOM)
CHAPTER 3 – ATOMS: BUILDING BLOCKS OF MATTER
CHAPTER 4 – ARRANGEMENT OF ELECTRONS IN ATOMS
OBJECTIVES:
 Understand the historical development of atomic theory
 Name the 5 essential points of Dalton's atomic theory
 Define the atom and identify its major components
 Explain isotopes in terms of atomic number & mass number and write nuclide symbols
 Use Avogadro's number to define the mole and molar mass
 Use dimensional analysis to solve problems involving conversions between
grams and moles and molecules
 Discuss the dual wave-particle nature of light
 Describe the Bohr model of the hydrogen atom
 Compare and contrast the Bohr model and the quantum model of the atom
 List the total number of electrons needed to fully occupy each main energy
level
 State the Aufbau principle, the Pauli Exclusion Principle, and Hund’s rule and
use them to write the electron configurations for elements in orbital notation,
standard electron configuration and noble gas notation.
Mass. State Frameworks:
2.1 Recognize discoveries from Dalton (atomic theory), Thomson (the electron), Rutherford (the
nucleus), and Bohr (planetary model of atom) and understand how these discoveries lead to the
modern theory.
2.2 Describe Rutherford’s “gold foil” experiment that led to the discovery of the nuclear atom.
Identify the major components (protons, neutrons, and electrons) of the nuclear atom and explain
how they interact.
2.3 Apply the laws of conservation of mass, constant composition (definite proportions), and multiple
proportions.
2.4 Write the electron configurations for the first twenty elements (hydrogen through calcium) of the
periodic table.
Important vocabulary:
Atom
Inner-shell electron
Mole
Photon
Atomic number
Isotope
Noble gas
quantum
Aufbau principle
Law of conservation
of mass
Noble-gas
configuration
Quantum theory
Avogadro’s number
Law of definite
proportions
Nuclear forces
Electron
configuration
Mass number
Nuclide
Hund’s rule
Molar mass
Pauli exclusion
principle
STUDY GUIDE
CONTENT:
 Dalton’s 5 postulates for atomic theory
 Components of the atom and their properties
 Law of conservation of mass and law of definite proportions
 Definitions of atomic number, mass number, and isotope
 Dual wave-particle nature of light
 Bohr model v. quantum model of the atom
 Aufbau principle, Hund’s rule, Pauli exclusion principle definitions
NON-MATH SKILLS:
 Use and write nuclide symbols to determine the number of protons, neutrons, and
electrons in atoms and ions
 Write electron configurations in standard format, orbital notation, and noble gas
notations
MATH SKILLS:
 Converting grams to moles to molecules and vice versa
 Calculating molar mass