Problem 39 - Chemistry: The Central Science

Question

For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table 2.3), and indicate whether it is a metal, metalloid, or nonmetal: (a) potassium, (b) iodine, (c) magnesium, (d) argon, (e) sulfur.

Step-by-Step Solution

Answer

(a) Potassium has the chemical symbol "K", belongs to Group 1 (Alkali Metals), and is a metal. (b) Iodine has the chemical symbol "I", belongs to Group 17 (Halogens), and is a nonmetal. (c) Magnesium has the chemical symbol "Mg", belongs to Group 2 (Alkaline Earth Metals), and is a metal. (d) Argon has the chemical symbol "Ar", belongs to Group 18 (Noble Gases), and is a nonmetal. (e) Sulfur has the chemical symbol "S", belongs to Group 16 (Chalcogens), and is a nonmetal.

Step 1: (a) Potassium

First, we need to find the chemical symbol of potassium. On the periodic table, we can see that the symbol for potassium is "K". Potassium is part of Group 1, which is also known as the Alkali Metals group. Since it is a member of a metal group, potassium is classified as a metal.

Step 2: (b) Iodine

To find the chemical symbol of iodine, look for it on the periodic table. The symbol for iodine is "I". Iodine is part of Group 17, which is called the Halogens group. Iodine is classified as a nonmetal.

Step 3: (c) Magnesium

We can find the chemical symbol for magnesium by looking at the periodic table. The symbol for magnesium is "Mg". Magnesium is part of Group 2, which is referred to as the Alkaline Earth Metals group. Since it is a member of a metal group, magnesium is classified as a metal.

Step 4: (d) Argon

To determine the chemical symbol of argon, find it in the periodic table. The symbol for argon is "Ar". Argon is part of Group 18, which is known as the Noble Gases group. Argon is classified as a nonmetal.

Step 5: (e) Sulfur

Finally, to find the chemical symbol for sulfur, we can look at the periodic table. The symbol for sulfur is "S". Sulfur is part of Group 16, which is called the Chalcogens group. Sulfur is classified as a nonmetal.

Key Concepts

Chemical Symbols

Bear in mind that chemical symbols are the shorthand used by scientists to represent elements in the periodic table. Each element has a unique one or two-letter symbol that is often derived from its name or historical name. For instance, the chemical symbol for potassium is 'K', which comes from its Latin name 'kalium'. When writing chemical symbols, the first letter is always capitalized, while the second is in lowercase, as with 'Mg' for magnesium.

Chemical symbols are incredibly efficient for writing chemical equations and formulas. For example, water is denoted as H₂O, representing two atoms of hydrogen bonded to one atom of oxygen. In the context of the exercise, identifying the symbol is the initial step before further classifying each element.

Group Naming in Periodic Table

The periodic table arranges elements into a grid-based on atomic number, but it also grouped them into columns called 'groups'. These groups contain elements with similar chemical properties due to having the same number of electrons in their outer shell. Group names can be numerical, ranging from 1 to 18, or can have specific names based on their characteristics.

For instance, Group 1 is also known as the Alkali Metals. They are highly reactive metals. Group 17 elements are called Halogens and are reactive nonmetals. Understanding group nomenclature helps in predicting the properties and reactivity of elements. Like during the exercise, knowing the group of an element, such as potassium belonging to Group 1, aids in the quick identification of it as a metal.

Metals, Metalloids, and Nonmetals

Elements are broadly classified into metals, metalloids, and nonmetals, based on their physical and chemical properties. Metals, like magnesium and potassium, are typically shiny, good conductors of heat and electricity, and are malleable and ductile. In contrast, nonmetals, such as sulfur and iodine, have more varied appearances and are generally poor conductors, brittle, and lack luster.

Metalloids act as a bridge between metals and nonmetals, possessing a mix of their properties; they are semiconductors and often used in electronics. Each category occupies specific areas on the periodic table, which allows us to predict their classification quickly. This classification is not only fundamental in understanding the element's properties but also crucial for predicting how different elements will chemically react with one another.