1. select the more electronegative element in this pair. a. f b. br 2. select the more electronegative element in this pair. a. se b. o 3. select the more electronegative element in this pair. a. si b. n 4. select the more electronegative element in this pair. a. mg b. na

F

O

N

Mg

Explanation

The key explanation here is that we need to know the trends in electronegativity value increase or decrease across the periods and down the group.

Across the periods, electronegativity is expected to increase. Hence, with the exception of the noble gases, the most electronegative elements are found further right on the periodic table. While electronegativity is expected to increase across the period, it decreases down the group.

Hence, if two elements are in the same group, further down we have the one with the less electronegative value. If two elements are in the same period, further right we have the more electronegative element.

1. F 2. O 3. Mg

Explanation: For electronegativity the trend are as follows.

Moving up group increases the electronegativity so F is in Group 7 together with Br. O and Se is in group 6. For Na and Mg the trend for elements in the same periods is electronegativity increases from left to right.

6.4 cm (max) - 25 cm (min)