Questions: Answer the following for a Se atom. Include the sign of the charge of the ion even if it is positive and place it in front of the number. For example, enter -3 not 3 - or 3.

Solution Steps

The atomic number of selenium (Se) is 34. This means a neutral selenium atom has 34 protons and 34 electrons.

Selenium typically forms a -2 ion. This is because selenium is in Group 16 of the periodic table and tends to gain 2 electrons to achieve a stable electron configuration similar to the nearest noble gas, krypton.

A neutral selenium atom has 34 electrons. When it gains 2 electrons to form a \(\text{Se}^{2-}\) ion, it will have: \[ 34 + 2 = 36 \text{ electrons} \]

Final Answer