Question

Which element in each of the following pairs has more nonmetallic character? (a) S or Te (b) \(\mathrm{Cl}\) or \(\mathrm{P}\) (c) \(\mathrm{Bi}\) or \(\mathrm{Br}\)

Short answer

(a) S, (b) Cl, (c) Br.

Step-by-step solution

Understanding Nonmetallic Character

Nonmetallic character refers to an element's ability to gain electrons. Elements with greater nonmetallic character are more likely to form anions. Nonmetallic character tends to increase across a period (from left to right) and decrease down a group (from top to bottom) in the periodic table.

Comparing Sulfur (S) and Tellurium (Te)

Sulfur (S) and Tellurium (Te) are both in Group 16 of the periodic table. Sulfur is above tellurium in the periodic table. Since nonmetallic character decreases down a group, sulfur has more nonmetallic character than tellurium.

Comparing Chlorine (Cl) and Phosphorus (P)

Chlorine (Cl) and Phosphorus (P) are in the same period (Period 3) of the periodic table, but chlorine is to the right of phosphorus. Nonmetallic character increases across a period, so chlorine has more nonmetallic character than phosphorus.

Comparing Bismuth (Bi) and Bromine (Br)

Bismuth (Bi) and Bromine (Br) are from different periods and groups. Bismuth is a metal in Group 15, and bromine is a nonmetal in Group 17. Nonmetals tend to have more nonmetallic character than metals, so bromine has more nonmetallic character than bismuth.

Key concepts

Nonmetallic Character

The nonmetallic character of an element describes its tendency to accept electrons and form negative ions, or anions. It is a property often associated with elements that are nonmetals. These elements tend to have high electron affinities and electronegativities.
When comparing different elements, those with a higher nonmetallic character are more effective at gaining additional electrons. This plays a key role in chemical reactions, providing insight into why certain elements behave in particular ways.
As a rule of thumb, nonmetallic character tends to increase when you move across a period from left to right on the periodic table. Conversely, it typically decreases as you go down a group. This trend is primarily due to the increasing nuclear charge across a period and the additional electron shells being added as you move down a group.

Periodic Table Trends

The periodic table of elements is structured in such a way that it illustrates periodic trends, including nonmetallic character. Understanding these trends is crucial for predicting how elements behave and interact with others.
One of the fundamental trends is that elements on the left side of the periodic table are generally metals, with low nonmetallic character. As you move toward the right, the elements become more nonmetallic. This is because the nuclear charge increases, making it easier for these atoms to attract electrons.
Another trend is that down a group, elements become less nonmetallic. This is due to the added distance between the nucleus and the outermost electrons, which weakens the nucleus's pull on additional electrons. Recognizing these general trends helps in determining which elements are more likely to gain electrons and become anions, forming compounds more readily with metals.

Element Comparison

When comparing elements in terms of nonmetallic character, it's important to consider their positions on the periodic table.
In the exercise, we compared pairs of elements:

• Sulfur (S) and Tellurium (Te)
• Chlorine (Cl) and Phosphorus (P)
• Bismuth (Bi) and Bromine (Br)

For the first pair, Sulfur is above Tellurium in Group 16, displaying more nonmetallic character since it is higher up the group. For the second pair, Chlorine is to the right of Phosphorus in Period 3, thus, it exhibits a greater nonmetallic character due to its position further right. Lastly, Bromine is more nonmetallic than Bismuth as it is a nonmetal in Group 17, while Bismuth is a metal in Group 15. Understanding these comparisons highlights the importance of periodic trends and helps to predict reactivity and chemical behavior.