Question

Give the Oxidation state for each metal species.

Fe---> Fe(CO)5--->Fe(CO)4I2

Answer 1

General guidance

Concepts and reason

The oxidation state of a metal is always positive. The oxidation state of a transition metal can be calculated by using the oxidation states of the other elements present in the compound.

Fundamentals

Transition metals show variable oxidation states.

Oxidation state is the number of electrons lost or gained by the element in during the formation of the compound. It may be positive, negative or 0.

Step-by-step

Step 1 of 3

(1)

The oxidation state of Fe in Fe is 0, as the metal is present in its elemental form.

Part 1

The oxidation state of Fe in Fe is 0.

Explanation | Hint for next step

The oxidation states of all the atoms in their elemental form are 0. If all the atoms are same then the electronegativity all the atoms is equal. Hence, the oxidation state is 0.

Step 2 of 3

(2)

Let the oxidation state of Fe is x.

The overall charge on the molecule, ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_5}$ is 0.

$\\begin{array}{l}\\\\x + 5\\left( 0 \\right) = 0\\\\\\\\x = 0\\\\\\end{array}$

Therefore, the charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_5}$is 0.

Part 2

The charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_5}$is 0.

Explanation | Hint for next step

As CO is a neutral molecule, it has a charge of 0. Substitute it and take the overall charge as 0 to calculate the oxidation state of Fe.

Step 3 of 3

(3)

Let the oxidation state of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_4}{{\\rm{I}}_2}{\\kern 1pt}$is x.

The overall charge on the molecule, ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_4}{{\\rm{I}}_2}{\\kern 1pt}$ is 0.

$\\begin{array}{l}\\\\x + 4\\left( 0 \\right) + 2\\left( { - 1} \\right) = 0\\\\\\\\x = + 2\\\\\\end{array}$

Therefore, the charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_4}{{\\rm{I}}_2}{\\kern 1pt}$is +2.

Part 3

The charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_4}{{\\rm{I}}_2}{\\kern 1pt}$is +2.

Explanation

As CO is a neutral molecule, it has a charge of 0. The oxidation state of I is -1. Substituted these two values to calculate the oxidation state of Fe.

Answer

Part 1

The oxidation state of Fe in Fe is 0.

Part 2

The charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_5}$is 0.

Part 3

The charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_4}{{\\rm{I}}_2}{\\kern 1pt}$is +2.

Answer only

Part 1

The oxidation state of Fe in Fe is 0.

Part 2

The charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_5}$is 0.

Part 3

The charge of Fe in ${\\rm{Fe}}{\\left( {{\\rm{CO}}} \\right)_4}{{\\rm{I}}_2}{\\kern 1pt}$is +2.