Question

Which elements are more electronegative: metals or nonmetals?

Short answer

Nonmetals are more electronegative than metals.

Step-by-step solution

Understanding Electronegativity

Electronegativity is the ability of an atom to attract electrons in a chemical bond. Typically, this value is greater for atoms that have a smaller atomic radius and a high effective nuclear charge.

Identifying Metals and Nonmetals

Metals are elements that are generally shiny, conductive, and tend to lose electrons in reactions. Nonmetals, on the other hand, are usually poor conductors, not shiny, and tend to gain electrons.

Comparing Electronegativity

Nonmetals have higher electronegativities compared to metals. In the periodic table, electronegativity increases across a period (from left to right) and decreases down a group. Since nonmetals are located on the right side of the periodic table, their electronegativity is generally higher than that of metals, which are located on the left.

Key concepts

Metals vs Nonmetals

Electronegativity is a fundamental concept to understanding how elements interact. To get a better grasp of this, let's compare metals and nonmetals, which differ significantly in their properties.
Metals are usually shiny and are good conductors of heat and electricity. They have a tendency to lose electrons and form positive ions (cations). This is because metals are typically found on the left side of the periodic table, where they possess lower electronegativity values.
In contrast, nonmetals are found on the right side of the periodic table. They are generally poor conductors of heat and electricity. Nonmetals tend to gain electrons in reactions, often forming negative ions (anions). This gain is facilitated by their higher electronegativity. Nonmetals usually seek to attract electrons, which is why they have higher electronegativity than metals.
In essence, the fundamental difference in electronegativity between metals and nonmetals largely determines how these elements will engage with others in chemical reactions.

Periodic Table Trends

A key pattern that emerges in the study of the periodic table is the trend in electronegativity across periods and down groups. Observing these trends helps in understanding why certain elements behave differently in chemical reactions.
In a given period of the periodic table, moving from left to right, the electronegativity of the elements increases. This is because the atomic radius decreases while the effective nuclear charge increases, making it easier for the atoms to attract electrons.
However, when moving down a group (or column), electronegativity decreases. This happens due to the increase in atomic radius and the addition of more electron shells, which reduces the pull of the nuclear charge on valence electrons.

• Higher location on the right side means higher electronegativity.
• Located at the bottom of a group means lower electronegativity.

This trend explains why, despite being nonmetals, some elements like halogens are extremely electronegative, while others like noble gases are less reactive due to their filled valence shells.

Chemical Bonds

Chemical bonds are the glue that holds atoms together in molecules and compounds. These can occur due to variations in electronegativity between different elements.
When two nonmetals interact, the chemical bond formed is typically covalent. Here, atoms share electrons in bonding pairs to achieve filled outer shells, aligning with their higher electronegativity values and the tendency to attract electrons.
On the other hand, when metals and nonmetals bond, the electronegativity difference is usually significant. This often results in the formation of ionic bonds. In ionic bonding, metals donate electrons because of their lower electronegativity, and nonmetals gain these electrons, resulting in oppositely charged ions that attract each other.
The electronegativity differences and resulting bond types dictate not only the structure of compounds but also their properties, such as melting and boiling points, electrical conductivity, and solubility. Understanding these differences is key to grasping chemical behavior and reactivity in a wide range of substances.