Problem 91 - General Chemistry: Principles and Modern Applications

Question

Refer only to the periodic table on the inside front cover and indicate which of the atoms, \(\mathrm{Bi}, \mathrm{S}, \mathrm{Ba}, \mathrm{As}\) and \(\mathrm{Ca},\) (a) is most metallic; (b) is most nonmetallic; (c) has the intermediate value when the five are arranged in order of increasing first ionization energy.

Step-by-Step Solution

Answer

The most metallic element is \(\mathrm{Ba}\), the most nonmetallic element is \(\mathrm{S}\), and the element with the intermediate first ionization energy is \(\mathrm{Ca}\).

Step 1: Finding the most metallic element

Identify the positions of \(\mathrm{Bi}, \mathrm{S}, \mathrm{Ba}, \mathrm{As}\) and \(\mathrm{Ca}\) on the periodic table. The most metallic element is the one located closest to the left and bottom. The element \(\mathrm{Ba}\) is the farthest to the left and bottom.

Step 2: Finding the most nonmetallic element

By the same logic, the most nonmetallic element is the one located furthest to the right and top. Here, this element is \(\mathrm{S}\).

Step 3: Finding the intermediate ionization energy

Knowing that ionization energy increases from left to right and bottom to top, arrange the given elements in ascending order of their ionization energy: \(\mathrm{Ba}, \mathrm{Bi}, \mathrm{Ca}, \mathrm{As}, \mathrm{S}\). The element with intermediate ionization energy is \(\mathrm{Ca}\) as it falls in the middle of this arrangement.

Key Concepts

Understanding Metallic Character

The metallic character of an element describes how readily an atom can lose electrons. In the periodic table, metallic character typically increases as we move from right to left and from top to bottom. This is because atoms on the left are more willing to lose an electron to become positively charged ions, making them metallic. Thus, elements situated in the lower left corner of the periodic table, like barium (Ba), exhibit the most metallic character.

• Generally, metals have properties like high electrical conductivity, malleability, and a shiny appearance.
• Elements such as cesium (Cs) and francium (Fr) are known as some of the most metallic elements.
• The metallic character decreases as you move across a period from left to right because elements tend to gain electrons to achieve a stable electron configuration.

To determine the most metallic element out of bismuth (Bi), sulfur (S), barium (Ba), arsenic (As), and calcium (Ca), find which is closest to the periodic table's bottom left.

Exploring Nonmetallic Character

Nonmetallic character refers to the tendency of an element to gain electrons. This character increases when moving from left to right and from bottom to top on the periodic table. Nonmetals are elements that prefer to gain or share electrons to achieve a full valence shell, rather than lose them. Hence, nonmetals are usually located in the upper right corner of the periodic table.

• Nonmetals tend to be poor conductors of heat and electricity and have high electronegativities.
• Noble gases, although nonmetals, are quite unreactive due to having complete electron shells.
• Fluorine (F) is considered the most nonmetallic because of its high tendency to attract electrons.

In the context of the given elements (Bi, S, Ba, As, Ca), sulfur (S) emerges as the most nonmetallic due to its placement on the periodic table.

Grasping Ionization Energy

Ionization energy is the amount of energy required to remove an electron from an atom in its gaseous state. Understanding ionization energy involves recognizing patterns across the periodic table.

• Ionization energy increases as you move up and to the right across the periodic table.
• This rise is due to increased nuclear charge, which holds the outer electrons more tightly, requiring more energy to remove them.
• Elements with low ionization energy are usually metals, while those with high ionization energy are nonmetals.

For the elements mentioned (Bi, S, Ba, As, Ca), Ca falls in the middle of their ionization energy values. Knowing this helps predict how these elements might chemically react or bond with others. Ca's intermediate ionization energy indicates it's more reactive than elements with higher ionization energy like S but less reactive than Ba, which has a lower ionization energy.