Lewis Dot Symbols & Chemical Bonds Flashcards
Valence
Combining Capacity
Which shell was important in the formation of chemical bonds?
The outer shells or valence shell of electrons is important in the formation of chemical bonds.
What are the Lewis Dot Symbols?
Lewis dot symbols as a short cut method for indicating the number of outer shell (valence) electrons in an atom.
2 Tendencies of Nature
(1) An increase in the entropy (molecular disorder) of a system.
(2) a decrease in the energy of a system
Chemical bond
The Sharing or Transferring of valence electrons.
Octet Rule
Natures attempt to obtain entirely filled shells or subshells. In most atoms this amounts to obtaining eight electrons. This observation is known as the octet rule.
Ionic Bond
are compromised of positive ions (Cations) and negative ions (anions) that attract each other due to their opposite electrical charge.
Electronegativity
the ability of an atom to attract an additional electron.
Oxidation
Any chemical reaction which involves the loss of electrons by some chemical specie is known as oxidation.
Reduction
Any chemical reaction which involves the gain of electrons by some chemical specie is known as reduction.
How are Ionic Bonds created?
Created when metal and nonmetal combine.
Ionic Bonds
Oppositely charged ions are attracted to each other by electrostatic forces creating a stable (strong) ionic bond.
Ionic Compounds- Melting and Boiling Points
Ionic compounds typically have melting temperatures of several hundred degrees celsius and boiling temperatures of a few thousand degrees Celsius.
Highly Charged Ions
(multiply-charged ions) should have stronger forces of attraction for each other with correspondingly higher melting and boiling temperatures.
Smaller Sized Ions
Small Sized ions should have stronger forces of attraction for each other correspondingly higher melting and boiling temperatures.
Trends in Solubility-
Ionic compounds containing less highly charged ions (singly charged ions) would be expected to be more soluble in water than ionic compounds containing more highly charged ions (Multiple charged ions)
Exceptions when Dealing with Trends in Solubility
(a) Heavy Metal Halides are less soluble than expected.
(b) Metallic hydroxides are less soluble than expected
(c) Metal sulfates are more soluble than expected.
Examples of Metal Halides
Silver(I), Mercury(I), and lead(II) halides
Exception to the Exception of Metallic Hydroxides
other than alkali metal hydroxides, such as sodium hydroxide)
Metallic Sulfates
Metallic Sulfates are more soluble than expected.
Effect on Ion Size
Larger sized ions —> More soluble
Smaller sized ions —> Less Soluble
