Check for Understanding
Complete the following on a sheet of paper. Be prepared to share
our your answer and process! (be sure to include significant figures
and units!)
 Diamonds are measured in carats, and 1 carat = 0.200g. The
density of diamond is 3.51g/cm3. What is the volume of a 5.0
carat diamond?
Questions?
 Solutions Manual Available
 Must stay in the classroom!
 Please utilize before school and/or after school

Learning Objectives
 I can use evidence to explain why atomic models have changed
through history.
 I can calculate the molar mass of a compound.
 I can name compounds and write formulas for binary
compounds, ternary compounds (those with polyatomic ions),
and acids.
 **Memorize the chemical formulas and charges of the
polyatomic ions and the most common transition metal ions.
 See list on blog!

Chapter 2: Atoms, Molecules, and Ions
 Pages 39-67
 Crash Course Video – Atomic Theory
 **Please note the following notes are just highlights. Please
read text for more detail.**
History of the Atom
 Atomic models have been around since Democritus
first thought about dividing matter into smaller and
smaller pieces until it could no longer be cut: atomos.
The idea of the atom was opposed by Aristotle and
took around 2500 years until scientific evidence was
used to revive the idea of atoms.
History of Atom Cont…
 John Dalton
 Based on the work of many scientists.
 Dalton’s 4-part model
 1. Each element is made of atoms.
 2. Atoms of a given element are identical; atoms of
different atoms are different in some fundamental ways.
 3. Atoms can combine to form compounds and a given
compound always has the same relative number and types
of atoms.
 4. Chemical reactions involve rearrangement of the ways
the atoms are bonded together. The atoms themselves are
not changed.
History of the Atom Cont…
Fundamental Chemical Laws
 The Law of Conservation of Mass
 Mass is neither created nor destroyed, it is conserved.
 The Law of Definite Proportions
 The law of definite proportions states that a given
compound always contains exactly the same proportions
of elements by mass. (water)
 The Law of Multiple Proportions
 The law of multiple proportions: When two elements
form a series of compounds, the ratio of masses of the
second element that combine with 1 gram of the first
element can always be reduced to the smallest whole
numbers.
The Atomic Structure
 The electron J.J. Thomson 1898-1903 – cathode ray tube
 Plum pudding model (positive charge with negative
electrons-plums)
 Robert Millikan -1909
 Oil drop experiment determined the mass of the
electron
 1911 Ernest Rutherford bombarded a thin sheet of
metal foil with alpha particles
 Nuclear atom idea rejected the plum pudding.
Isotopes
 Atoms with the same number of protons but
different numbers of neutrons.
 Isotopes show almost identical chemical
properties because the number of electrons
remains the same and the chemistry of an
atom is due to its electrons.
 * Most elements are a mixture of isotopes*
Atomic (Z) & Mass (A) Number
 Atomic Number (Z)
 Number of protons
written as a subscript
in front of chemical
symbol
 Mass Number ( A)
 Total number of
protons and neutrons
written as a
superscript in front of
the chemical symbol
Practice
 Review Packet
 Model
 5 Minutes
Molecules
 Chemical bonds
 Forces that hold atoms together in compounds
(i.e. sharing electrons)
 Covalent bonds share electrons to form
molecules.
 Chemical formula is used to represent a
molecule.
 Chemical symbol used to identify element
and subscripts indicate the relative
number of atoms. (water, octane, oxygen)
Ions
 Ionic bonds electrons are transferred.
 Chemical bond results from the attractions
among ions.
 Ion is an atom or group of atoms that has
a net positive (cation) or net negative
charge (anion). (table salt)
 Ionic solid- salt – contains oppositely
charged ions.
Periodic Table Intro
 Most elements are metal
 Metals have
characteristic physical
properties
 Good conductors of
heat and electricity
 Malleability
 Ductility
 Lustrous
appearance (often)
 Metals tend to lose
electrons (cations)
 Nonmetals
 Upper right of PT (except
Hydrogen)
 Gain electrons (anion)
 Typically bond via covalent
bonds
 Why does this make
sense?
 Dr. HOFINBrCl (Diatomics)
Periodic Table Intro Cont…
 Arrangement
 Vertical columns = Groups or Families (similar chemical
properties….such as?)
 Alkali Metals
 Alkaline Earth Metals
 Halogens
 Noble Gases
 Horizontal rows = Periods
 We will cover the Periodic Table in much more detail later!
Nomenclature
Practice
 Review Packet
 Ionic Compounds
 Compounds with Hydrogen
 Covalent Compounds
Lab Safety
 Lab Safety Video
 Lab Safety Contract
 Lab Expectations
Lab Materials
 Grab a Green Lab Book (DO NOT WRITE IN/ON!)
 Grab a Black Lab Binder (DO NOT WRITE IN/ON!)
 Please record the number to both on class roster!
 The rest of today is for you to begin working on Chapter 1 & 2!
 ASK QUESTIONS…Work together!
For Tomorrow…
 Complete the LAST TWO pages of review packet.
 Complete the following problems from the textbook:
 # 16, 17, 19, 20, 21, 22, 41, 42 (Starting on page #70)
 Read Lab A: Empirical Formula (Black Binder) and complete pre-
lab, FOR THURSDAY!!
 Read Chapter 3 - Stoichiometry pages 77-113.
Have a WONDERFUL afternoon!!