Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 109 - General Chemistry - Spring 2011

Lecture Notes 5: 28 January

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Chemical Periodicity

Look at the Periodic Chart.

Periods

Groups

Terms etc.:

Chemical Nomenclature

Nomenclature is covered in section 2.8 (pp 57-67) in your textbook-you should be able to do the examples and exercises in the assigned problems. Note also the Discussion Module, OWL and these notes.

First, let's look at the the elements that you should learn the names of, as listed on the web:

HSU Chemistry Elements Names

The common ions and acids and bases are summarized on the handout and the web:

HSU Chemistry Table of Ions & HSU Chemistry Table of Acids

Note that formulae are more or less written with the elements ordered by electronegativity (elements on the right side precede those on the left).

Covalent vs. Ionic compounds:

This distinction will be important in some aspects of naming chemical compounds.

IUPAC vs traditional names

There are two common naming systems:

The IUPAC/Stock system

This is the modern, systematic scheme developed by the International Union of Pure and Applied Chemists.

Recognize these traditional names for metal ions:

FYI - Nomenclature examples etc.

Polyatomic ions

In these ions a group of atoms are covalently bound to each other and functions as a single charged particle. You should memorize the following names and be able to write formulas for the compounds and vice versa:

  • ammonium ion:
  • cyanide ion:
  • carbonate ion:
  • nitrate ion:
  • nitrite ion:
  • phosphate ion:
  • sulfite ion:
  • oxalate ion:
  • hydroxide ion:
  • acetate ion:
  • bicarbonate ion:
  • sulfate ion:

Compounds

Salts (Ionic Compounds) and Bases

Ions of opposite charge may combine to form neutral compounds. Thus the ions must combine in ratios such that the charges cancel. When the negative ion is hydroxide, the compound is considered a base. Examples:

  • potassium chloride:
  • sodium hydrogen sulfate (sodium bisulfate):
  • aluminum hydroxide:
  • iron(III) carbonate:
  • iron(III) hydrogen carbonate (iron(III) bicarbonate):
  • ammonium phosphate:
  • copper(I) oxalate:
  • calcium hydroxide:

Acids

Acids are compounds which give hydrogen ions (protons) in solution. There are two common inorganic acid types in terms of nomenclature:

  • Hydro-( )-ic acids: If hydrogen combines with a nonmetallic element the resulting acid is named by adding the prefix hydro- and replacing -ide by -ic. Examples:
    • HBr:
    • HCl:
  • Oxo acids: When non-metallic elements react with oxygen the resulting products often react with water or form ions which can react with protons to from acids. These oxo acids are named by replacing the -ate suffix with -ic acid or -ite suffix with -ous acid. Examples:
    • carbonic acid:
    • sulfuric acid:
    • acetic acid:
    • nitric:
    • Chloroacids (Hydrochlorous acid - Perchloric acid)

The HSU Chemistry Table of Common Acids is a useful summary of the acids you should be familiar with.

Special names

These compounds don't follow the rules, but have been in common use so long they keep their traditional names. Examples:

  • Water:
  • methane:
  • ammonia:
  • hydrogen peroxide:

The Nuclear Atom

Atoms are now known to consist of three different types of particles: electrons, protons and neutrons (the common form of one very important atom, hydrogen, has only two kinds: a proton and an electron). The protons and neutrons reside in a small inner portion called the nucleus while the electrons reside in a relatively large cloud centered on the nucleus. Important properties of these particles are listed in the table below:

 Particle

Charge

Relative Mass

Mass

Electron (e-) -1 1/1840 9.11 x 10-28g
Proton (p or H+) +1 ª1 1.67 x 10-24g
Neutron (n) 0  ª1  1.67 x 10-24g

Some important terms which you must know are:

Isotopes

Isotopes are forms of elements which differ only in the number of neutrons. This means different isotopes of the same element have essentially the same chemical properties but slightly different physical properties. They can also differ substantially in terms of their nuclear stability. Let's look at some examples of isotopes:

 Symbol Z A p n e-
14 6 14 6 8 6
238U6+ 92 238 92 146 86
35Cl- 17 35 17 18 18
 18O2-  8 18 8  10 10 

You should be able to fill in the blanks in a table like this with, the aid of a periodic table, on a quiz.

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© R A Paselk

Last modified 28 January 2011