Question

Which member of each pair is less metallic? (a) I or O (b) Be or Ba (c) Se or Ge

Short answer

O is less metallic than I, Be is less metallic than Ba, Se is less metallic than Ge.

Step-by-step solution

Understand metallic character

Metallic character refers to how easily an atom can lose electrons. Elements with higher metallic character are typically more reactive and are found on the left side and towards the bottom of the periodic table, whereas non-metallic elements are found on the right side and towards the top.

Compare Iodine (I) and Oxygen (O)

Oxygen (O) is located in Group 16 and Period 2 of the periodic table, while Iodine (I) is in Group 17 and Period 5. Since metallic character increases down a group and decreases across a period, Oxygen (O) is less metallic than Iodine (I).

Compare Beryllium (Be) and Barium (Ba)

Beryllium (Be) is located in Group 2 and Period 2, while Barium (Ba) is in Group 2 and Period 6. Since metallic character increases down a group, Beryllium (Be) is less metallic than Barium (Ba).

Compare Selenium (Se) and Germanium (Ge)

Selenium (Se) is located in Group 16 and Period 4, while Germanium (Ge) is in Group 14 and Period 4. Since metallic character increases from right to left across a period, Selenium (Se) is less metallic than Germanium (Ge).

Key concepts

periodic table trends

The periodic table is organized in a way that helps us understand various properties of elements, including their metallic character. As you move from left to right across a period (a row of the periodic table), elements become less metallic. This is because they tend to gain electrons rather than lose them.
However, as you move down a group (a column of the periodic table), elements become more metallic.
This is due to the increasing size of the atoms, which makes it easier for them to lose electrons. For example, in our exercise, Oxygen (O) is in Period 2 and Group 16, making it less metallic than Iodine (I) in Period 5 and Group 17.

• Across a period: Metallic character decreases
• Down a group: Metallic character increases

Understanding these trends is key to predicting the behaviors of elements in chemical reactions.

reactivity of elements

Reactivity of elements is closely related to their metallic character.
Metals tend to lose electrons easily and react vigorously, especially with nonmetals like Oxygen or Chlorine.
For example, Beryllium (Be) is less reactive due to its smaller size and higher electronegativity compared to Barium (Ba). Barium readily loses electrons to form positive ions, making it highly reactive.
Conversely, non-metals like Oxygen (O) are highly reactive because they tend to gain electrons to achieve a full outer shell. Iodine (I), being lower than Oxygen in the group, exhibits a lower reactivity because its atoms hold onto their electrons more strongly.

• Metals lose electrons easily, increasing reactivity
• Non-metals gain electrons to achieve stability
• Reactivity trends are crucial for predicting chemical interaction

metallic vs non-metallic elements

Metals and non-metals have distinct properties. Metals, such as Beryllium (Be) and Barium (Ba), are usually shiny, conduct electricity, and are malleable. They lose electrons easily, making them highly conductive and reactive.
Non-metals, like Oxygen (O) and Selenium (Se), are typically dull, poor conductors, and brittle when solid. They tend to gain electrons, making them less conductive and reactive differently compared to metals. For instance, Germanium (Ge), which has both metallic and non-metallic properties (making it a metalloid), shows less metallic character than Selenium (Se) and is more likely to gain electrons in a chemical reaction.

• Metals: Shiny, conductive, lose electrons easily
• Non-metals: Dull, poor conductors, gain electrons
• Metalloids: Exhibit mixed properties of both