Problem 82 - General Chemistry: Principles and Modern Applications

Question

Without referring to any tables or listings in the text, mark an appropriate location in the blank periodic table provided for each of the following: (a) the fifthperiod noble gas; (b) a sixth-period element whose atoms have three unpaired \(p\) electrons; (c) a \(d\) -block element having one \(4 \mathrm{s}\) electron; (d) a \(p\) -block element that is a metal.

Step-by-Step Solution

Answer

The solution to the exercise is: a) Xenon (Xe) b) Polonium (Po) c) Scandium (Sc) d) Aluminium (Al)

Step 1: Identify the fifth-period noble gas

Noble gases are found in group 18 of the periodic table. To find the fifth-period noble gas, move down to the fifth row and then across to group 18. This is element Xenon (Xe).

Step 2: Find a sixth-period element with three unpaired p electrons

This refers to elements in the nitrogen group (Group 15) as elements in this group have 5 electrons in their outer shell, 2 of which are paired, leaving 3 unpaired. We need the element in the sixth period, and that will be Polonium (Po).

Step 3: Locate a d-block element with one 4s electron

The presence of one 4s electron means that this element has already filled the 3d sublevel and moved onto the 4s sublevel. The elements in the first column of the d-block represent this configuration. In the fourth period, the element that matches this rule is Scandium (Sc).

Step 4: Identifying a p-block metal

Moving to the right side of the periodic table, most of the metals in the p-block are found in groups 13 and 14 (also known as the Boron and Carbon groups). One metal from this block can be Aluminium (Al), located in the third period of group 13.

Key Concepts

Noble Gases

Noble gases are a group of chemical elements with quite unique characteristics. You can find them in Group 18 of the periodic table. They are known for being very stable and unreactive. This is because their outer electron shell is completely filled.
This full outer shell means they are not looking to gain or lose electrons.

• Helium ( He) is the first noble gas, present in the first period.
• Xenon ( Xe) is the noble gas found in the fifth period. It is part of the exercise question.
• These gases are introduced at different periods in the table, as you move down from light gases like Helium, to heavier ones like Radon.

Because of their special stability, noble gases are often used in lighting and in applications where reactions are not desired. Think of neon signs, for example, or the argon used in light bulbs to prevent corrosion. Understanding why these gases are inert helps in understanding chemical reactivity patterns.

d-block Elements

The d-block elements, often known as transition metals, are those that you find in the central part of the periodic table.
These metals have their outer electrons in the d subshell, which gives them unique properties like variable oxidation states and colored compounds.

• Scandium ( Sc) is an example, located in the fourth period.

A special feature of these elements is their electron configuration. For Scandium, it particularly includes one 4s electron, after filling the 3d subshell. This configuration allows these elements to participate in a variety of chemical reactions. In fact, this electron transition capability is central to many of their industrial and chemical uses, like catalysts in reactions, or in forming interesting compounds.

p-block Elements

The p-block encompasses groups 13 to 18 on the periodic table.
These elements have their distinguishing electrons occupy a p orbital. Within this section, you'll find a variety of metals and non-metals. Consider Aluminum ( Al), which belongs to group 13 and sits within the p-block.
What makes p-block unique?

The elements here range from metalloids to metals, and to nonmetals like the noble gases.

They are known for various properties including oxidation states and versatile bonding.

• Some are well known for their roles in forming life-sustaining compounds, such as those containing carbon and nitrogen.
• Others, like aluminum, are used for their specific physical properties. Aluminum's lightweight yet strong structure makes it ideal for use in manufacturing and construction.

The p-block’s variety showcases the breadth of chemistry present in this section.

Unpaired Electrons

Unpaired electrons are electrons that are alone in an orbital, without another electron with the opposite spin to pair with. Elements with unpaired electrons are usually more reactive as these electrons can easily engage in chemical bonding.
This is particularly the case for elements from Group 15, such as Polonium ( Po) in the sixth period. Polonium has three unpaired p electrons out of the five in its outer shell.

• This means that its electronic configuration is inclined to form bonds more easily.
• Unpaired electrons contribute to the magnetic properties of substances. For instance, materials can be paramagnetic if they have one or more unpaired electrons.

Recognizing the importance of unpaired electrons helps in predicting and understanding the chemical behavior and reactions of elements.