Question

checkpoint 2: locate f, o, br, se on the periodic table. which would you expect to be the least reactive? br o f se

Explanation:

• Trend in reactivity for non - metals: In the periodic table, for non - metals, reactivity decreases down a group and increases across a period (from left to right).
• Position of elements:
• F (Fluorine): It is in Group 17 (Halogens) and Period 2. It is the most electronegative element and very reactive as it only needs one electron to complete its octet.
• O (Oxygen): In Group 16 and Period 2. It is reactive as it needs two electrons to complete its octet.
• Br (Bromine): In Group 17 and Period 4. It is less reactive than F (since reactivity decreases down a group for non - metals) but more reactive than Se.
• Se (Selenium): In Group 16 and Period 4. It is less reactive than O (due to the increase in atomic size down the group, which makes it less likely to gain electrons as effectively as smaller non - metals in the same group).

Answer:

Se