10/25/22 - Redox Reactions & Oxidation Numbers Flashcards
What is a redox reaction?
A reaction that involves a transfer of electrons between reactants.
What is oxidation?
A loss of electrons
What is reduction?
A gain of electrons
What is the oxidizing agent?
The reduced substance in a redox reaction
What is the reducing agent?
The oxidized substance in a redox reaction
When elements react to form an ionic compound, is it a redox reaction?
Yes
Why is the formation of covalent compounds from neutral elements a redox reaction?
Because there is a shift in the electrons. The even distribution of electrons in the reactants becomes uneven in the product (atoms in covalent compounds have different electronegativities).
What is the oxidation number of an atom in elemental form (Na, O2, H2, etc.)?
0
What is the oxidation number of a monoatomic ion?
Same as the ion’s charge.
What is the sum of the oxidation numbers for the atoms in a compound?
0
What is the sum of the oxidation numbers for the atoms in a polyatomic ion?
Same as the ion’s charge.
What is the oxidation number for Group 1A elements in compounds?
+1
What is the oxidation number for Group 2A elements in compounds?
+2
What is the oxidation number for hydrogen in compounds with nonmetals?
+1
But, with metals and boron, it’s -1, such as in NaH
What is the oxidation number for fluorine in compounds?
-1
What is the oxidation number for oxygen in peroxides and in all other compounds?
-2 in all compounds, except -1 in peroxides. Does not include compounds with F.
What is the oxidation number for halogens in compounds?
-1, except in compounds with oxygen and other halogens lower in the group.
When an element’s oxidation number increases in a reaction, does that show oxidation or reduction?
Oxidation
