Problem 30 - Chemistry and Chemical Reactivity

Question

Here are symbols for five of the seven elements whose names begin with the letter \(\mathrm{B}: \mathrm{B}, \mathrm{Ba}, \mathrm{Bk}, \mathrm{Bi},\) and \(\mathrm{Br}\) Match each symbol with one of the descriptions below. (a) a radioactive element (b) a liquid at room temperature (c) a metalloid (d) an alkaline earth element (e) a group 5 A element

Step-by-Step Solution

Answer

(a) Bk, (b) Br, (c) B, (d) Ba, (e) Bi

Step 1: Identify the radioactive element

The symbol for a radioactive element among them is \(\mathrm{Bk}\). Bk stands for Berkelium, which is a synthetic element and is radioactive.

Step 2: Identify the liquid at room temperature

Among the given elements, the liquid at room temperature is \(\mathrm{Br}\). Br stands for Bromine, which is one of the only two elements in the periodic table that is liquid at room temperature.

Step 3: Identify the metalloid

The symbol for a metalloid among the given elements is \(\mathrm{B}\). B stands for Boron, which is classified as a metalloid because it has properties intermediate between those of metals and non-metals.

Step 4: Identify the alkaline earth element

The alkaline earth element among the options is represented by the symbol \(\mathrm{Ba}\). Ba stands for Barium, which is part of the alkaline earth metals group.

Step 5: Identify the group 5 A element

The symbol for the group 5 A element is \(\mathrm{Bi}\). Bi stands for Bismuth, which is a group 5 A element (or group 15 in the modern IUPAC numbering).

Key Concepts

Radioactive Elements

Radioactive elements are atoms that have unstable nuclei. This means they decay over time, releasing energy in the form of radiation. Understanding radioactive elements is important because they have significant impacts on the environment and health, and they are useful in various technology and medicine applications.

• **Decay and Radiation**: Unstable nuclei release particles and energy as they transition into more stable forms. This process is called radioactive decay. The energy released can be harmful to living organisms, which is why handling radioactive materials requires safety precautions.
• **Applications**: In medicine, radioactive isotopes can help diagnose and treat diseases. For example, cancer treatment sometimes involves targeting tumors with radiation.
• **Berkelium (Bk)**: Identified in our exercise, Berkelium is a synthetic element. It's produced in tiny amounts in reactors or particle accelerators and is not found naturally. Berkelium is a highly radioactive element and must be handled with care.

Liquid Elements at Room Temperature

A unique feature of the periodic table is that only a few elements can exist as liquids at room temperature. This makes them special and interesting to study.

• **Definition**: An element is considered a liquid at room temperature (around 20 to 25°C or 68 to 77°F) if it possesses fluid-like properties without being heated or cooled.
• **Bromine (Br)**: Among our options, Bromine is the element that is a liquid at room temperature. It is one of the only two elements, the other being mercury, that are liquids under these conditions. Bromine is a halogen, and it's useful in various industries, especially in flame retardants and pesticides.
• **Properties**: Bromine is a reddish-brown liquid with a strong, unpleasant odor. It's corrosive and toxic, so it must be handled carefully.

Metalloids

Metalloids are fascinating because they have characteristics of both metals and non-metals. They often act as semiconductors and are essential in the tech industry.

• **Characteristics**: Metalloids are solid at room temperature, have a metallic appearance, and can conduct electricity better than non-metals but not as well as metals, making them useful as semiconductors.
• **Boron (B)**: In our exercise, Boron is identified as a metalloid. It is used in many applications, including in ceramics, detergents, and as a semiconductor in the electronics industry.
• **Applications and Importance**: Because of their mixed properties, metalloids are crucial in advancements in technology, specifically in computer chips and solar cells.

Alkaline Earth Metals

Alkaline earth metals are a group of elements in the periodic table that are known for their reactive properties and occurrence in the earth's crust.

• **Group Characteristics**: The alkaline earth metals include Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium. They are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.
• **Reactivity and Uses**: These metals typically form compounds like oxides, and their compounds have widespread applications. For instance, Barium, denoted as Ba in our exercise, is used in drilling fluids for oil wells and in paints and glassmaking.
• **Properties**: Alkaline earth metals have two electrons in their outer shell, which they readily lose to achieve a full outer electron shell, creating ionic bonds. They react with water, though not as violently as alkali metals.