Answer: The given transition metal ions in order of decreasing number of unpaired electrons are as follows.

Explanation:
In atomic orbitals, the distribution of electrons of an atom is called electronic configuration.
The electronic configuration in terms of noble gases for the given elements are as follows.
- Atomic number of Fe is 26.
![Fe^{3+} - [Ar] 3d^{5}](https://tex.z-dn.net/?f=Fe%5E%7B3%2B%7D%20-%20%5BAr%5D%203d%5E%7B5%7D)
So, there is only 1 unpaired electron present in
.
- Atomic number of Mn is 25.
![Mn^{4+} - [Ar]3d^{3}](https://tex.z-dn.net/?f=Mn%5E%7B4%2B%7D%20-%20%5BAr%5D3d%5E%7B3%7D)
So, there are only 3 unpaired electrons present in
.
- Atomic number of V is 23.
![V^{3+} - [Ar] 3d^{2}](https://tex.z-dn.net/?f=V%5E%7B3%2B%7D%20-%20%5BAr%5D%203d%5E%7B2%7D)
So, there are only 2 unpaired electrons present in
.
- Atomic number of Ni is 28.
![Ni^{2+} - [Ar] 3d^{8}](https://tex.z-dn.net/?f=Ni%5E%7B2%2B%7D%20-%20%5BAr%5D%203d%5E%7B8%7D)
So, there will be 2 unpaired electrons present in
.
- Atomic number of Cu is 29.
![Cu^{+} - [Ar] 3d^{10}](https://tex.z-dn.net/?f=Cu%5E%7B%2B%7D%20-%20%5BAr%5D%203d%5E%7B10%7D)
So, there is no unpaired electron present in
.
Therefore, given transition metal ions in order of decreasing number of unpaired electrons are as follows.

Thus, we can conclude that given transition metal ions in order of decreasing number of unpaired electrons are as follows.

Whenever I have tests like these, I make a quizlet with each part zoomed in and then answer it that way.
Answer: fourth option, 10.8 kJ
Explanation:
The <em>heat of fusion</em>, also named latent heat of fusion, is the amount of heat energy required to change the state of a substance from solid to liquid (at constant pressure).
The data of the <em>heat of fusions</em> of the substances are reported in tables and they can be shown either per mole or per gram of substance.
In this case we have that the<em> heat of fusion for water </em>is reported per mole: <em>6.02 kJ/mole</em>.
The formula to calculate <em>how many kJ of heat (total heat) are needed to completely melt 32.3 g of water, given that the water is at its melting point</em> is:
- Heat = number of moles × heat of fusion
The calculations are:
- number of moles = mass / molar mass
number of moles = 32.3 g / 18.015 g/mol = 1.79 mol
- Heat = 1.79 mol × 6.02 kJ / mol = 10.8 kJ ← answer