204.0920-It have 7 significant digits
Answer:
correct option: A and D
Explanation:
generally element from d block can for ion with multiple charge and having incomplete outershell means element do not have fullfiled or half filed orbital because in these case it takes more energy to remove valence shell electron.
Answer : The standard cell potential of the reaction is, -1.46 V
Explanation :
The given balanced cell reaction is,
Here, chromium (Cr) undergoes oxidation by loss of electrons and act as an anode. Lead (Pb) undergoes reduction by gain of electrons and thus act as cathode.
The standard values of cell potentials are:
Standard reduction potential of lead ![E^0_{[Pb^{2+}/Pb]}=-0.13V](https://tex.z-dn.net/?f=E%5E0_%7B%5BPb%5E%7B2%2B%7D%2FPb%5D%7D%3D-0.13V)
Standard reduction potential of chromium ![E^0_{[Cr^{3+}/Cr]}=1.33V](https://tex.z-dn.net/?f=E%5E0_%7B%5BCr%5E%7B3%2B%7D%2FCr%5D%7D%3D1.33V)
Now we have to calculate the standard cell potential for the following reaction.
![E^0=E^0_{[Pb^{2+}/Pb]}-E^0_{[Cr^{3+}/Cr]}](https://tex.z-dn.net/?f=E%5E0%3DE%5E0_%7B%5BPb%5E%7B2%2B%7D%2FPb%5D%7D-E%5E0_%7B%5BCr%5E%7B3%2B%7D%2FCr%5D%7D)
Therefore, the standard cell potential of the reaction is, -1.46 V
Roughly, Aufbau Principle says that in an atom or an ion, electrons enter the shell with low energy first before entering the shell with high energy.
An atom has shells around its nucleus. Electrons enter these shells and orbit around the nucleus of an atom. To say about the properties of these shells, the shell nearest to the nucleus has the lowest energy. The farther the shell from the nucleus, the higher its energy. Aufbau Principle states that electrons enter the closest shell to the nucleus first since it has the lowest energy. When that shell has its maximum number of electrons is can hold, then the next electron will enter the second-closest shell to the nucleus, which has higher energy than the first shell.
