Question

Describe the trend of oxidizing and reducing property along a period and a group of the periodic table.

Short answer

Answer: The oxidizing property of elements increases from left to right across a period and decreases as we move down a group. The reducing property follows an opposite trend, decreasing from left to right across a period and increasing as we move down a group.

Step-by-step solution

Defining Oxidation and Reduction Properties

Oxidation refers to the process of an atom losing one or more electrons, whereas reduction involves an atom gaining one or more electrons. An element that readily loses electrons is considered as having good reducing properties, whereas an element that readily gains electrons is considered as having strong oxidizing properties.

Understanding Ionization Energy and Electron Affinity

Ionization energy (IE) is the energy required to remove an electron from a gaseous atom or ion. Elements with higher ionization energy require more energy to remove an electron. Electron affinity (EA) is the energy change that accompanies the addition of an electron to a gaseous atom or ion. Elements with higher electron affinity release more energy when they gain an electron.

Oxidizing and Reducing Properties Across a Period

As we move from left to right across a period in the periodic table, the number of protons in the nucleus increases, which increases the nuclear charge. This leads to a stronger attraction between the valence electrons and the nucleus. Consequently, ionization energy increases, and elements become more difficult to oxidize (lose electrons). On the other hand, the electron affinity also increases across a period, and elements become better oxidizing agents as they gain electrons more readily. In summary, the reducing property decreases, and the oxidizing property increases as we move from left to right across a period.

Oxidizing and Reducing Properties Down a Group

As we move down a group in the periodic table, the number of electron shells increases, leading to larger atomic size. This causes a weaker attraction between the valence electrons and the nucleus as the electrons are located further away from the nucleus. As a result, ionization energy decreases, making it easier for elements to lose electrons, and their reducing property increases. On the other hand, electron affinity generally decreases as we move down a group, making elements weaker oxidizing agents as they do not gain electrons as readily. In summary, the reducing property increases, and the oxidizing property decreases as we move down a group. In conclusion, the oxidizing property of elements increases from left to right across a period and decreases as we move down a group. The reducing property follows an opposite trend, decreasing from left to right across a period and increasing as we move down a group.