How many electrons can Lead gain or lose when it forms an ion
The Correct Answer and Explanation is:
Correct Answer:
Lead (Pb) can lose 2 or 4 electrons when it forms an ion. Therefore, it commonly forms either Pb²⁺ or Pb⁴⁺ ions.
Explanation
Lead is a metal located in group 14 (IVA) of the periodic table. Its atomic number is 82, which means a neutral lead atom contains 82 electrons. When lead forms ions, it does so by losing electrons, as metals tend to do. The number of electrons lost determines the oxidation state of the ion.
Lead can form two stable oxidation states: +2 and +4. This means lead can lose either two electrons or four electrons to form Pb²⁺ or Pb⁴⁺ ions, respectively. The ability of lead to form two different ions is due to the involvement of both the outermost electrons and some inner electrons that are still relatively loosely held.
The most common and stable oxidation state of lead is +2. This occurs when lead loses the two electrons from its outermost 6p orbital, resulting in a Pb²⁺ ion. This form is more stable because the remaining electrons are held more tightly, and the ion reaches a relatively lower energy state.
Lead can also lose four electrons to form a Pb⁴⁺ ion, but this is less common and less stable. Removing four electrons requires more energy and typically happens in compounds where lead bonds with very electronegative elements, such as oxygen or fluorine. An example is lead(IV) oxide (PbO₂).
The existence of both +2 and +4 ions in lead is a result of the inert pair effect, a phenomenon seen in heavier elements of the p-block. This effect makes the s-electrons more reluctant to participate in bonding as we move down the group, making the +2 state more favorable.
In summary, lead can lose either 2 or 4 electrons when forming ions, leading to Pb²⁺ or Pb⁴⁺. Among these, the Pb²⁺ ion is more stable and more commonly found in chemical compounds.
