Finding Oxidation Number - Organic Chemistry
Card 1 of 28
Compared to oxygen in water, the oxygen in hydrogen peroxide has valence electron(s).
Compared to oxygen in water, the oxygen in hydrogen peroxide has valence electron(s).
Tap to reveal answer
To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is 
. The oxidation number of hydrogen is +1. Since there are two of them, the hydrogen atoms contribute to a charge of +2. The water molecule is neutral; therefore, the oxygen must have an oxidation number of 
to balance the charge. The formula for hydrogen peroxide is 
. Using the same logic as water, we can determine that hydrogen contributes +2. We have two oxygen atoms in this case; therefore, each oxygen atom will have an oxidation number of 
to give a charge of 
. This will balance the charges and provide a neutral hydrogen peroxide molecule.
Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of 
suggests one extra valence electron and a charge of 
suggests two extra valence electrons. An oxygen typically has six valence electrons. The oxygen in water has 
oxidation number; therefore, it will have two extra valence electrons (eight total). On the other hand, oxygen in hydrogen peroxide will have one extra valence electron (seven total); therefore, oxygen in hydrogen peroxide has one less valence electron than oxygen in water.
To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is
Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of
← Didn't Know|Knew It →
Which of the following is true regarding the correct oxidation number of potassium in potassium bromide?
Which of the following is true regarding the correct oxidation number of potassium in potassium bromide?
Tap to reveal answer
Potassium bromide has a formula of 
. This molecule is made up of an alkali metal (potassium) and a halogen (bromine). Alkali metals have one valence electron that they readily lose to obtain octet whereas halogens have seven valence electrons and they readily gain an electron to obtain octet. Recall that losing an electron will give you a 
oxidation number whereas gaining an electron will give you a 
oxidation number. This means that alkali metals always have an oxidation number of 
whereas halogens always have an oxidation number of 
; therefore, potassium has an oxidation number of 
.
Potassium bromide has a formula of
← Didn't Know|Knew It →
The oxidation numbers of calcium and chromium in the compound 
are and , respectively.
The oxidation numbers of calcium and chromium in the compound
Tap to reveal answer
Calcium is in the second group of the periodic table, so its oxidation number will always be 
. This is true for all alkaline earth metals.
As for chromium, the dichromate anion (
) has an overall charge of 
. Each oxygen atom will always have an oxidation number of 
as well, so the oxygens would have a total negative charge of 
. The sum of the oxidation numbers have to equal the overall charge, so chromium must be used to balance the negative charges from the oxygen. To bring the overall charge to 
, the two chromiums have to have total charge of 
, giving each an oxidation number of 
.
Calcium is in the second group of the periodic table, so its oxidation number will always be
As for chromium, the dichromate anion (
← Didn't Know|Knew It →
What is the oxidation number of the manganese in potassium permanganate?
What is the oxidation number of the manganese in potassium permanganate?
Tap to reveal answer
Manganese is a transition metal, so its oxidation number is more variable than the other elements of the compound. Oxygen is almost always 
. Potassium is almost always 
. The sum of the oxygens and the potassium is 
.
The compound is neutral, so the manganese is 
to balance the net molecular charge.
Manganese is a transition metal, so its oxidation number is more variable than the other elements of the compound. Oxygen is almost always
The compound is neutral, so the manganese is
← Didn't Know|Knew It →
A student reacts sodium chloride and lithium bromide. He collects the products in a jar and performs several tests on them. He concludes that product A has a metal and a nonmetal and that the metal has an oxidation number of 
whereas the nonmetal has an oxidation number of 
. What can you conclude from these results?
A student reacts sodium chloride and lithium bromide. He collects the products in a jar and performs several tests on them. He concludes that product A has a metal and a nonmetal and that the metal has an oxidation number of
Tap to reveal answer
The reaction stated in this question is as follows.
This is a double replacement reaction. Both products contain a metal (an alkali metal) and a nonmetal (a halogen). The oxidation number of all alkali metals (first column of periodic table) is 
and of all halogens (seventh column of periodic table) is 
. The results stated in the question seem invalid because a halogen can never have an oxidation number of 
.
The reaction stated in this question is as follows.
This is a double replacement reaction. Both products contain a metal (an alkali metal) and a nonmetal (a halogen). The oxidation number of all alkali metals (first column of periodic table) is
← Didn't Know|Knew It →
Which of the following is the correct oxidation number of manganese in Manganese(III) oxide?
Which of the following is the correct oxidation number of manganese in Manganese(III) oxide?
Tap to reveal answer
Manganese(III) oxide has a formula of 
. The oxidation number of oxygen is 
. Since there are three of them, the oxygen atoms contribute to a charge of 
. To maintain the neutrality of the molecule, manganese must balance the 
charge (meaning contribute 
charge). There are two manganese atoms; therefore, each manganese atom will have an oxidation number of 
and contribute 
charge.
Manganese(III) oxide has a formula of
← Didn't Know|Knew It →
In the compound 
, what is the oxidation number of 
?
In the compound
Tap to reveal answer
Generally, oxygen has an oxidation number of 
, and hydrogen has an oxidation number of 
. If we multiply 
by the number of oxygen atoms in the compound (
), we get an overall charge of 
on the oxygen. If we multiply 
by the number of hydrogen atoms in the compound (
), we get an overall charge of 
on the hydrogen. The sum of 
and 
is 
. We can see that 
is a neutral molecule, so the charge on 
would have to balance out the 
charge on the rest of the molecule. To obtain a charge of 
, the oxidation number on 
must then be 
.
Generally, oxygen has an oxidation number of
← Didn't Know|Knew It →
Compared to oxygen in water, the oxygen in hydrogen peroxide has valence electron(s).
Compared to oxygen in water, the oxygen in hydrogen peroxide has valence electron(s).
Tap to reveal answer
To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is . The oxidation number of hydrogen is +1. Since there are two of them, the hydrogen atoms contribute to a charge of +2. The water molecule is neutral; therefore, the oxygen must have an oxidation number of to balance the charge. The formula for hydrogen peroxide is . Using the same logic as water, we can determine that hydrogen contributes +2. We have two oxygen atoms in this case; therefore, each oxygen atom will have an oxidation number of to give a charge of . This will balance the charges and provide a neutral hydrogen peroxide molecule.
Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of suggests one extra valence electron and a charge of suggests two extra valence electrons. An oxygen typically has six valence electrons. The oxygen in water has oxidation number; therefore, it will have two extra valence electrons (eight total). On the other hand, oxygen in hydrogen peroxide will have one extra valence electron (seven total); therefore, oxygen in hydrogen peroxide has one less valence electron than oxygen in water.
To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is
Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of
← Didn't Know|Knew It →
Which of the following is true regarding the correct oxidation number of potassium in potassium bromide?
Which of the following is true regarding the correct oxidation number of potassium in potassium bromide?
Tap to reveal answer
Potassium bromide has a formula of . This molecule is made up of an alkali metal (potassium) and a halogen (bromine). Alkali metals have one valence electron that they readily lose to obtain octet whereas halogens have seven valence electrons and they readily gain an electron to obtain octet. Recall that losing an electron will give you a oxidation number whereas gaining an electron will give you a oxidation number. This means that alkali metals always have an oxidation number of whereas halogens always have an oxidation number of ; therefore, potassium has an oxidation number of .
Potassium bromide has a formula of
← Didn't Know|Knew It →
The oxidation numbers of calcium and chromium in the compound are and , respectively.
The oxidation numbers of calcium and chromium in the compound
Tap to reveal answer
Calcium is in the second group of the periodic table, so its oxidation number will always be . This is true for all alkaline earth metals.
As for chromium, the dichromate anion () has an overall charge of . Each oxygen atom will always have an oxidation number of as well, so the oxygens would have a total negative charge of . The sum of the oxidation numbers have to equal the overall charge, so chromium must be used to balance the negative charges from the oxygen. To bring the overall charge to , the two chromiums have to have total charge of , giving each an oxidation number of .
Calcium is in the second group of the periodic table, so its oxidation number will always be
As for chromium, the dichromate anion (
← Didn't Know|Knew It →
What is the oxidation number of the manganese in potassium permanganate?
What is the oxidation number of the manganese in potassium permanganate?
Tap to reveal answer
Manganese is a transition metal, so its oxidation number is more variable than the other elements of the compound. Oxygen is almost always . Potassium is almost always . The sum of the oxygens and the potassium is .
The compound is neutral, so the manganese is to balance the net molecular charge.
Manganese is a transition metal, so its oxidation number is more variable than the other elements of the compound. Oxygen is almost always
The compound is neutral, so the manganese is
← Didn't Know|Knew It →
A student reacts sodium chloride and lithium bromide. He collects the products in a jar and performs several tests on them. He concludes that product A has a metal and a nonmetal and that the metal has an oxidation number of whereas the nonmetal has an oxidation number of . What can you conclude from these results?
A student reacts sodium chloride and lithium bromide. He collects the products in a jar and performs several tests on them. He concludes that product A has a metal and a nonmetal and that the metal has an oxidation number of
Tap to reveal answer
The reaction stated in this question is as follows.
This is a double replacement reaction. Both products contain a metal (an alkali metal) and a nonmetal (a halogen). The oxidation number of all alkali metals (first column of periodic table) is and of all halogens (seventh column of periodic table) is . The results stated in the question seem invalid because a halogen can never have an oxidation number of .
The reaction stated in this question is as follows.
This is a double replacement reaction. Both products contain a metal (an alkali metal) and a nonmetal (a halogen). The oxidation number of all alkali metals (first column of periodic table) is
← Didn't Know|Knew It →
Which of the following is the correct oxidation number of manganese in Manganese(III) oxide?
Which of the following is the correct oxidation number of manganese in Manganese(III) oxide?
Tap to reveal answer
Manganese(III) oxide has a formula of . The oxidation number of oxygen is . Since there are three of them, the oxygen atoms contribute to a charge of . To maintain the neutrality of the molecule, manganese must balance the charge (meaning contribute charge). There are two manganese atoms; therefore, each manganese atom will have an oxidation number of and contribute charge.
Manganese(III) oxide has a formula of
← Didn't Know|Knew It →
In the compound , what is the oxidation number of ?
In the compound
Tap to reveal answer
Generally, oxygen has an oxidation number of , and hydrogen has an oxidation number of . If we multiply by the number of oxygen atoms in the compound (), we get an overall charge of on the oxygen. If we multiply by the number of hydrogen atoms in the compound (), we get an overall charge of on the hydrogen. The sum of and is . We can see that is a neutral molecule, so the charge on would have to balance out the charge on the rest of the molecule. To obtain a charge of , the oxidation number on must then be .
Generally, oxygen has an oxidation number of
← Didn't Know|Knew It →
The oxidation numbers of calcium and chromium in the compound are and , respectively.
The oxidation numbers of calcium and chromium in the compound
Tap to reveal answer
Calcium is in the second group of the periodic table, so its oxidation number will always be . This is true for all alkaline earth metals.
As for chromium, the dichromate anion () has an overall charge of . Each oxygen atom will always have an oxidation number of as well, so the oxygens would have a total negative charge of . The sum of the oxidation numbers have to equal the overall charge, so chromium must be used to balance the negative charges from the oxygen. To bring the overall charge to , the two chromiums have to have total charge of , giving each an oxidation number of .
Calcium is in the second group of the periodic table, so its oxidation number will always be
As for chromium, the dichromate anion (
← Didn't Know|Knew It →
What is the oxidation number of the manganese in potassium permanganate?
What is the oxidation number of the manganese in potassium permanganate?
Tap to reveal answer
Manganese is a transition metal, so its oxidation number is more variable than the other elements of the compound. Oxygen is almost always . Potassium is almost always . The sum of the oxygens and the potassium is .
The compound is neutral, so the manganese is to balance the net molecular charge.
Manganese is a transition metal, so its oxidation number is more variable than the other elements of the compound. Oxygen is almost always
The compound is neutral, so the manganese is
← Didn't Know|Knew It →
Compared to oxygen in water, the oxygen in hydrogen peroxide has valence electron(s).
Compared to oxygen in water, the oxygen in hydrogen peroxide has valence electron(s).
Tap to reveal answer
To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is . The oxidation number of hydrogen is +1. Since there are two of them, the hydrogen atoms contribute to a charge of +2. The water molecule is neutral; therefore, the oxygen must have an oxidation number of to balance the charge. The formula for hydrogen peroxide is . Using the same logic as water, we can determine that hydrogen contributes +2. We have two oxygen atoms in this case; therefore, each oxygen atom will have an oxidation number of to give a charge of . This will balance the charges and provide a neutral hydrogen peroxide molecule.
Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of suggests one extra valence electron and a charge of suggests two extra valence electrons. An oxygen typically has six valence electrons. The oxygen in water has oxidation number; therefore, it will have two extra valence electrons (eight total). On the other hand, oxygen in hydrogen peroxide will have one extra valence electron (seven total); therefore, oxygen in hydrogen peroxide has one less valence electron than oxygen in water.
To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is
Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of
← Didn't Know|Knew It →
Which of the following is true regarding the correct oxidation number of potassium in potassium bromide?
Which of the following is true regarding the correct oxidation number of potassium in potassium bromide?
Tap to reveal answer
Potassium bromide has a formula of . This molecule is made up of an alkali metal (potassium) and a halogen (bromine). Alkali metals have one valence electron that they readily lose to obtain octet whereas halogens have seven valence electrons and they readily gain an electron to obtain octet. Recall that losing an electron will give you a oxidation number whereas gaining an electron will give you a oxidation number. This means that alkali metals always have an oxidation number of whereas halogens always have an oxidation number of ; therefore, potassium has an oxidation number of .
Potassium bromide has a formula of
← Didn't Know|Knew It →
A student reacts sodium chloride and lithium bromide. He collects the products in a jar and performs several tests on them. He concludes that product A has a metal and a nonmetal and that the metal has an oxidation number of whereas the nonmetal has an oxidation number of . What can you conclude from these results?
A student reacts sodium chloride and lithium bromide. He collects the products in a jar and performs several tests on them. He concludes that product A has a metal and a nonmetal and that the metal has an oxidation number of
Tap to reveal answer
The reaction stated in this question is as follows.
This is a double replacement reaction. Both products contain a metal (an alkali metal) and a nonmetal (a halogen). The oxidation number of all alkali metals (first column of periodic table) is and of all halogens (seventh column of periodic table) is . The results stated in the question seem invalid because a halogen can never have an oxidation number of .
The reaction stated in this question is as follows.
This is a double replacement reaction. Both products contain a metal (an alkali metal) and a nonmetal (a halogen). The oxidation number of all alkali metals (first column of periodic table) is
← Didn't Know|Knew It →
Which of the following is the correct oxidation number of manganese in Manganese(III) oxide?
Which of the following is the correct oxidation number of manganese in Manganese(III) oxide?
Tap to reveal answer
Manganese(III) oxide has a formula of . The oxidation number of oxygen is . Since there are three of them, the oxygen atoms contribute to a charge of . To maintain the neutrality of the molecule, manganese must balance the charge (meaning contribute charge). There are two manganese atoms; therefore, each manganese atom will have an oxidation number of and contribute charge.
Manganese(III) oxide has a formula of
← Didn't Know|Knew It →