Question

Question: Which of the elements 1-36 have two unpaired electrons in the ground state?

Short answer

The elements with two unpaired electrons from atomic number in the periodic system of elements are: carbon(c), oxygen(O), silicon(Si), sulphur(S), titanium(Ti), nickel(Ni), germanium(Ge), selenium(Se).

Step-by-step solution

Step 1:

• Carbon$\to \left[\mathrm{He}\right]2{\mathrm{s}}^{2}2{\mathrm{p}}^2$
• Oxygen$\to \left[\mathrm{He}\right]2{\mathrm{s}}^{2}2{\mathrm{p}}^4$
• Silicon$\to \left[\mathrm{Ne}\right]3{\mathrm{s}}^{2}3{\mathrm{p}}^2$
• Sulfur$\to \left[\mathrm{Ne}\right]3{\mathrm{s}}^{2}3{\mathrm{p}}^4$
• Titanium$\to \left[\mathrm{Ar}\right]3{\mathrm{d}}^{2}4{\mathrm{s}}^2$
• Nickel$\to \left[\mathrm{Ar}\right]3{\mathrm{d}}^{8}4{\mathrm{s}}^2$
• Germanium$\to \left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^{2}4{\mathrm{p}}^3$
• Selenium$\to \left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^{2}4{\mathrm{p}}^4$

Step 2:

Carbon has 2 unpaired electrons in its$2\mathrm{p}$ orbital.

Oxygenhas 2 unpaired electrons in its $2\mathrm{p}$orbital.

Silicon has 2 unpaired electrons in its$3\mathrm{p}$ orbital.

Sulfur has 2 unpaired electrons in its $3\mathrm{p}$orbital.

Titanium has 2 unpaired electrons in its $3\mathrm{d}$orbital.

Nickel has 2 unpaired electrons in its $3\mathrm{d}$orbital.

Germanium has 2 unpaired electrons in its $4\mathrm{p}$orbital.

Selenium has 2 unpaired electrons in its $4\mathrm{p}$orbital.