The electronic configuration 4f2 corresponds to the ion Pr3+, which is derived from the element Praseodymium (Pr).
Neutral Praseodymium (Pr) has the atomic number 59, and its ground state electronic configuration is:
[Xe] 4f3 6s2
When it forms the ion Pr3+, three electrons are removed. These are typically removed first from the outermost orbitals (6s and 4f):
This leaves the configuration as [Xe] 4f2.
Therefore, the correct answer is option (B): Pr3+
A quantity \( X \) is given by: \[ X = \frac{\epsilon_0 L \Delta V}{\Delta t} \] where:
- \( \epsilon_0 \) is the permittivity of free space,
- \( L \) is the length,
- \( \Delta V \) is the potential difference,
- \( \Delta t \) is the time interval.
The dimension of \( X \) is the same as that of:
Lanthanoids are at the top of these two-row, while actinoids are at the bottom row.
Lanthanoids are inclusive of 14 elements, with atomic numbers 58-71:
These elements are also called rare earth elements. They are found naturally on the earth, and they're all radioactively stable except promethium, which is radioactive. A trend is one of the interesting properties of the lanthanoid elements, called lanthanide contraction.