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Gen Chem 1 Notes
General Chemistry I (CHM2045)
University of South Florida
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Gen Chem 1 Notes 2 Chemical Bonds
- compounds: a substance composed of two or more elements in a fixed, definite proportion
- compounds are composed of atoms held together by chemical bonds, which result from the attractions between the charged particles 2 representing compounds: chemical formulas and molecular models
- chemical formula indicates the elements present in the compound and the relative number of atoms or ions of each.
- chemical symbol for each element
- subscript: number of atoms or ions (omit “1”) 2 types of chemical formulas
- chemical formulas can generally be categorized into two different types:
- empirical formula gives u the simplest whole-number ratio of atoms of each element ina compound. (simplified version of molecular formula)
- molecular formula gives the actual number of atoms of each element in a molecule of a compound. Elements that exist as molecules
Diatomic molecules: H2, N2, O2, F2, CL2, Br2, I
The most common form of elemental sulfur exists as S
BrINIHOF 2 The period table
Dimitri Mendeleev in Russia and Lothar Meyer in Germany independently recognized that there was a periodic relationship among the properties of the elements known at that time. Example: Lithium, sodium, and potassium are all shiny, conduct heat and have similar chemical properties 2 the modern periodic table
periodic law: the properties of the elements are periodic functions of their atomic numbers
a modern periodic table arranges the elements in increasing order of their atomic numbers and groups atoms with similar properties in the same vertical column
periods or series: horizontal rows
groups: vertical columns
- the letter A is used for the presentative elements 1A to 8A and the letter B for the transition elements.
- the numbers 1-18 are used for the columns from left to right 2 Classifications of elements
Metals are shiny, malleable, good conductors of heat and electricity.
Nonmetals appear dull, poor conductors of heat and electricity
Metalloids conduct heat and electricity moderately well, and possess some properties of metals and some properties of nonmetals. 2 Classifications of Elements
Main group elements: Groups: 1A – VIII A (or 1,2, 13-18) -Transition metals: groups: IB – VIII B(or 3-12)
Inner transition metals
- Two rows at the bottom of the periodic table
- Lanthanides: top row
- Actinides: bottom row
- Two rows at the bottom of the periodic table
Gen Chem 1 Notes
Course: General Chemistry I (CHM2045)
University: University of South Florida
