Question

Using only the periodic table as your guide, select the most electronegative atom in each of the following sets: (a) Se, \(\mathrm{Rb}, \mathrm{O}, \mathrm{In} ;\) (b) \(\mathrm{Al}, \mathrm{Ca}, \mathrm{C}, \mathrm{Si} ;\) (c) Ge, As, P, Sn; (d) Li, \(\mathrm{Rb}, \mathrm{Be}, \mathrm{Sr}\)

Short answer

The most electronegative atoms in each set are: (a) O (oxygen), (b) C (carbon), (c) P (phosphorus), and (d) Be (beryllium).

Step-by-step solution

Set (a): Se, Rb, O, In

In set (a), we need to select the most electronegative atom among Se, Rb, O, and In. Following the trends in the periodic table, it can be observed that O (oxygen) is present in the second row and next to the right within the same row, making it the most electronegative among the four elements. Therefore, the most electronegative atom in set (a) is O.

Set (b): Al, Ca, C, Si

In set (b), we need to select the most electronegative atom among Al, Ca, C, and Si. We can see that C (carbon) is located upper and to the left of the other elements in the periodic table. Thus, based on the electronegativity trends, carbon is the most electronegative element in set (b). Therefore, the most electronegative atom in set (b) is C.

Set (c): Ge, As, P, Sn

In set (c), we need to select the most electronegative atom among Ge, As, P, and Sn. P (phosphorus) is located upper than the other elements in the periodic table, and left to As within the same row, making it the most electronegative among the four elements. Therefore, the most electronegative atom in set (c) is P.

Set (d): Li, Rb, Be, Sr

In set (d), we need to select the most electronegative atom among Li, Rb, Be, and Sr. Comparing the positions of these elements in the periodic table, Be (beryllium) is the element with the highest position and the farthest to the right within the same row, which makes it the most electronegative element in set (d). Therefore, the most electronegative atom in set (d) is Be.

Key concepts

Understanding the Periodic Table

The periodic table is a comprehensive chart that organizes all the known elements according to their atomic properties. This table is crucial for understanding elements' behavior and relationships with one another. It is divided into rows called periods and columns referred to as groups or families.

One of the significant uses of the periodic table is that it allows scientists and students alike to determine properties of elements, such as their states of matter, electronegativity, and types, whether they are metals, nonmetals, or metalloids. Elements are displayed in order of increasing atomic number, which is the number of protons in an atom's nucleus. The layout is designed to illustrate periodic trends, such as elements with similar properties falling within the same group, making it easier to predict their characteristics and chemical reactions.

Chemical Elements and Their Unique Characteristics

Chemical elements are the building blocks of all matter in the universe. Each element has a unique atomic structure that defines its physical and chemical properties, such as melting point, reactivity, and, as mentioned in our exercise, electronegativity.

An element's atomic structure includes the number of protons, neutrons, and electrons, which are key to understanding an element's identity. Protons carry a positive charge, neutrons are neutral, and electrons bear a negative charge. The number of protons in the nucleus of an atom is termed the atomic number and is fundamental in classifying the element. In our exercise, the atomic properties, particularly the electron configuration, are what determine the electronegativity of an element.

Atomic Properties Influencing Behavior

Atomic properties such as the number of valence electrons and the size of the atom play a significant role in determining an element's chemical behavior. For example, electronegativity, which is the ability of an atom to attract electrons towards itself in a bond, greatly depends on these atomic characteristics.

The more valence electrons an atom has, generally, the more electronegative it will be. This occurs because elements strive to have a full outer electron shell, which resembles the electron configuration of noble gases, the most stable elements. Additionally, smaller atoms tend to be more electronegative because the distance between the nucleus and the valence electrons is shorter, allowing the nucleus to exert a stronger attractive force on the bonding electrons.

Trends in the Periodic Table Explaining Electronegativity

The periodic table shows patterns in the properties of elements, which are called periodic trends. One such trend is the variation in electronegativity, a vital concept in our exercise.

Electronegativity increases across a period from left to right due to the addition of more protons in the nucleus without a significant increase in the shielding effect of electrons in the same energy level. This leads to a greater attraction for bonding electrons. As we move up a group, electronegativity also increases because atoms have fewer electron shells, so the nucleus can pull the bonding electrons more strongly.

In the exercise's four sets, identifying the most electronegative element in each set is a matter of applying this trend. In summary, we look across the periods and up the groups to find the element with the highest electronegativity. This kind of knowledge allows students not only to solve the problems at hand but also to grasp the underlying principles governing the behavior of elements in the periodic table.