Download AlBr3 E IO Ionic FU C O Cov Molec C IO Cov Molec Sn E N/A N/A

Chem 4
Name: ANSVER KEY
1. Which of the following statements of the atomic theory proposed by John Dalton at
the beginning of the 19th century are not quite true in light of modern atomic
physics? Rewrite each statement to reflect the current understanding of the atomic
theory.
An element is made up of atoms. All
Atoms cannot be created or destroyed.
atoms of a given element are identical.
2.
All atoms of a given element have the same
number of protons in the nucleus. They may
differ in the number of neutrons. Chemically the
atoms of a given element are virtually
indistinguishable: the types of chemical
reactions are the same; the rates may slightly
differ for different isotopes.
Atoms cannot be created or destroyed in
chemical reactions. In chemical reactions the
old bonds between atoms are broken down
and new bonds are formed. Atoms, however,
can be created or destroyed in nuclear
reactions: radioactive decays, nuclear fission
and fusion.
All atoms of one element have the same
mass. Atoms of two different elements
have different masses.
Atoms of different elements may
combine in the ratio of small, whole
numbers to form compounds.
The main characteristic of an element is the
atomic number. Two elements differ from each
other by their atomic numbers. In fact, atoms of
two different elements may have masses that
are very close to each other. For example,
39.9624 amu for an atom of argon-40 and
39.9640 amu for an atom of potassium-40.
This is often the case for many compounds,
especially inorganic. It was always the case for
compounds known to Dalton. Most organic
compounds (whose composition was not
known to Dalton) do not follow that rule:
C12H22O11 (sugar), C27H46O (cholesterol),
C17H21NO4 (cocaine).
Fill out the following table. Use abbreviation N/A for “not applicable”.
Basic unit
(atom,
Organic or Ionic or
molecule,
Inorganic? covalent?
or formula
unit)?
Substance
Name
Formula
or
Symbol
Element or
compound?
Aluminum
bromide
AlBr3
E
IO
Ionic
FU
Methanol
CH3OH
C
O
Cov
Molec
Nitogen dioxide
NO2
C
IO
Cov
Molec
Tin
Sn
E
N/A
N/A
Atom
Iron (II)
carbonate
FeCO3
C
IO
Ionic
FU
Ammonium
nitrite
NH4NO2
IO
Ionic
FU
Sulfur trioxide
SO3
C
IO
Cov
Molec
Tetraphosporus
P4
E
N/A
N/A
Molec