Bell Ringer
1) Get out your chapter notes and
answer the following question:
1) Why is the Periodic Table a
great resource tool?
2) How many atoms of each
element are in the following
compound?
1) NaCl
2) H2O
3) Ca3(PO4)2
Schedule
1. Bell Ringer
2. PT Notes
3. Practice Problems
HOMEWORK: Finish Practice Problems
& Study elements!!
I CAN……identify an
unknown solution using
physical properties.
Teachers open the door, but you must
enter by yourself. 
Elements & Compounds
Elements
• Can not be broken
down
• Building blocks of all
substances
• Most Pure substances
(that are compounds)
can be broken down
(sugar, salt, water)
• Above 92 on periodic
table, except
plutonium, do not
occur naturally
• Smallest unit retaining
properties of element:
atom
Elements in Nature
• Br and Hg liquid at room temp
• 11 are gases
• H2, N2, O2, F2, Cl2, He2, Ne, Ar, Kr, Xe,
Rn
• Rest are solids
• Names and Symbols: one or two
letters, first letter is always capitalized
H = Hydrogen
He = Helium
Li = Lithium
Be = Beryllium
Periodic Table
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Atomic number: whole number increasing as you move left to right…
Elements arranged with similar chemical properties in columns: Families or groups
Group 1A: alkali metals
Group 2A: alkaline earth metals
Group 3A: Boron Family
Group 4A: Carbon Family
Group 5A: Nitrogen Family (Pnictigens)
Group 6A: Oxygen Family (Chalcogens)
Group 7A: Halogens
Group 8A: Noble Gases
Groups 1- 7A and Noble Gases are referred to as Representative Elements
Middle of table is Transition Elements
Metals, Non Metals &
Metalloids
Metals
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Most of P. table
Solids @ room temp
Hg is liquid
Lustrous
Good conductors: heat,
electricity
Malleable
Ductile
High mp and density
Ex: Al, Ag, Zn, Sn
Generally combine with non
metals to form COMPOUNDS
Alloys are mixtures of
metals
– HOMOGENEOUS mixtures:
brass, bronze, steel,
coinage
Nonmetals
• Nonlustrous
• Low mp and densities
• Poor conductors of
electricity and heat
• Br, liquid at room temp
• C, P, S, Se, I solid at room
temp
• Rest of nonmetals are
gases at room temp
• Carbon (diamond and
graphite in nature)
• Nonmetals combine with
each other to form
compounds
– CO2, CH4, C4H10, SO2
Metalloids
• Have properties of both metals and
nonmetals
• B, Si, As, Ge, Sb, Te, Po
• B, Si and Ge are used in semi-conductors
Elements in Natural State
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Elements exist in mixtures or compounds
Most elements are reactive
Ag, Po and Au can be found in pure form in nature
Nobel gases: Group 8A: non-reactive, for the most part
Krypton forms KrF2, a colorless solid, on reaction with fluorine.
– Helium, neon and argon form no known compounds.
– Xenon forms a wide range of compounds with oxygen and fluorine.
Diatomics
• Contain two
atoms (can
never exist
alone bc too
reactive)
• Seven diatomics
• H2, N2, O2, F2,
Cl2, Br2 and I2
Compounds
• Two or more
elements
• Chemically
combined
• Definite
proportions by
mass
• Can decompose
chemically into
simpler
substances
• Atoms are in
whole number
ratios
• NO FRACTIONS
Molecules
• Smallest uncharged unit of a
compound
• Union of two or more atoms
• H2O
• Two hydrogen atoms bonded to one
oxygen atom
• *Remember, all molecules are
compounds but not all compounds
are molecules. (ex: PO4-3)
Ions
• Positively or negatively charged atom
or group of atoms
• Cation is positive ion: loss of
electron(s)
• Anion is negative ion: gain
electron(s)
• Ionic bond is formed between cation
and anion
• NaCl, NaOH, Ca(NO3)2
Chemical Formulas
• Abbreviation for compound
• Symbols and subscripts
• How many atoms of each elements are
in the following compounds?
• KBr
• PbCl3
• CaCO3
• Mg(OH)2
• H2SO4
• Ca(NO3)2