Periodic Trends - Electronegativity Answers (Page 2 of 3) in pdf

nucleus to the outer electrons, since atoms get larger as you move down in

a group.

Go to the Periodic Table Live! at Click on the

“Graph/Table” button in the upper right corner. Use this graphing feature to answer the

questions below.

Start by clicking the “Deselect All” button above the miniature periodic table. You want

to be able to choose which elements, groups, and periods will be graphed to answer this

worksheet.

On the graph to the right of your screen, go to the drop-down menus below x and y (this

is where you can choose the value for your x- and y-axis). You should graph atomic

number (under atomic properties) and the electron affinity (also under atomic properties).

6. Do you notice a general trend (don’t worry about a few outliers—look for the

overall trend) in the electronegativity across the period you chose? Try a couple

of other periods, is the trend consistent? Describe the trend. Is it consistent with

your predictions?

It’s fairly consistent, and there is a general upward trend. Elements are more

electronegative to the right side of the periodic table.

7. Can you explain why you see this trend as you move across a period?

It is consistent with the trend we see with IE and EA; we know that they are

related to EN based on Mulliken’s equation. Both of them relate to the pull of the

nucleus on the electrons, as the atomic number (and number of protons in the

nucleus) goes up, the pull also goes up.

8. Deselect all and choose any one group in the periodic table, with the same x- and

y-axes that you used above. Look at a few more groups, but avoid the transition

metals (i.e., groups 3–12). Do you see a trend in the electronegativity down a

group? Is it consistent between groups? Is it consistent with your predictions?

It generally decreases.

9. Can you explain why you see this trend?

It relates to the IE and EA (see 5b, above). When electrons are farther away from

the nucleus (in shells that are farther away), there is less attraction for the

nucleus, and the inner electrons shield the outer electrons, also decreasing the

attraction. There is also some contribution from electron configuration.

10. Water is a molecule composed of one oxygen and two hydrogen atoms (H

O).

Using the chart-and-sort feature, determine the electronegativity of hydrogen and

Periodic Trends - Electronegativity Answers Page 2