Question

for a nickel (ni) atom in its ground electronic state:
how many electrons are there in the 4s orbital? number (enter an integer.)
how many electrons are there in the 3d orbitals? number (enter an integer.)
how many electrons are there in the 4p orbitals? number (enter an integer.)
how many unpaired electrons are there? number (enter an integer.)
to what block does this atom belong? (enter s, p, d, or f.)

Explanation:

Step1: Determine the electron configuration of Ni

The atomic number of Ni is 28. The electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{8}\).

Step2: Analyze the number of electrons in each orbital

• For the \(4s\) orbital: From the electron configuration \(4s^{2}\), the number of electrons is \(2\).
• For the \(3d\) orbitals: From \(3d^{8}\), the number of electrons is \(8\).
• For the \(4p\) orbitals: Since the electron configuration does not fill the \(4p\) orbitals (\(4p^{0}\)), the number of electrons is \(0\).

Step3: Determine the number of unpaired electrons

In the \(3d\) orbitals (\(3d^{8}\)), using Hund's rule. The \(3d\) sub - shell has 5 orbitals. First, each orbital gets one electron (5 electrons), and then the remaining 3 electrons pair up. So, there are \(2\) unpaired electrons.

Step4: Determine the block

Elements with the last - filled sub - shell as \(d\) are in the \(d\) - block.

Answer:

• Number of electrons in \(4s\) orbital: \(2\)
• Number of electrons in \(3d\) orbitals: \(8\)
• Number of electrons in \(4p\) orbitals: \(0\)
• Number of unpaired electrons: \(2\)
• Block: \(d\)