Question

Would you predict that a \(\mathrm{Kr}\) atom has high electroneg ativity or low electronegativity? Predict the relative electronegativity of \(\mathrm{Kr}\) and \(\mathrm{F}\).

Short answer

Krypton has low electronegativity, while Fluorine has high electronegativity.

Step-by-step solution

Understanding Electronegativity

Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself. It is an important concept in chemistry as it affects the nature of chemical bonds.

Examining Krypton's Position in the Periodic Table

Krypton (Kr) is a noble gas located in Group 18 of the periodic table. Noble gases are known for their complete valence electron shells, typically leading them to have low electronegativity since they do not tend to form bonds.

Examining Fluorine's Position in the Periodic Table

Fluorine (F) is located in Group 17, which is known as the halogens. It is at the top of its group and is the most electronegative element in the periodic table. Elements with high electronegativity, like fluorine, readily attract electrons.

Comparing Electronegativity of Kr and F

By examining their positions in the periodic table, we can predict that Krypton, with its stable electron configuration as a noble gas, has low electronegativity. In contrast, Fluorine, being the most electronegative element, has very high electronegativity.

Key concepts

Noble Gases

Noble gases, such as Krypton (Kr), are situated in Group 18 of the periodic table and are known for their stability. This stability is primarily due to their complete valence shell of electrons, which makes them less inclined to participate in chemical reactions. Unlike other elements, noble gases already have a full complement of electrons in their outermost energy level.
This electron configuration results in them having very low electronegativity.

• Electronegativity in noble gases is usually minimal because they have little tendency to attract additional electrons.
• The complete electron shell makes noble gases nearly inert, meaning they rarely form chemical bonds.

This is why krypton and its fellow noble gases are often found in elemental form, rather than bonded with other elements.

Periodic Table

The periodic table is an organized chart of all known elements, arranged by increasing atomic number. Elements are grouped into columns known as groups, and rows known as periods. This arrangement helps illustrate patterns and trends in element properties, such as electronegativity.
Electronegativity typically increases across a period (from left to right) and decreases down a group (from top to bottom).

• As you move across a period, the number of protons in the nucleus increases, which enhances the atom's ability to attract electrons.
• Moving down a group, the increased distance of the valence electrons from the nucleus and additional electron shielding affect their electronegativity negatively.

Understanding the position of an element in the periodic table provides a quick way to predict its reactivity and bonding behavior.

Chemical Bonds

Chemical bonds are connections between atoms that hold them together in molecules. Electronegativity plays a crucial role in the formation of these bonds. When two atoms form a bond, the difference in their electronegativities will determine the bond's nature:

• Non-polar covalent bonds form when the electronegativity difference is minimal, leading to an equal sharing of electrons.
• Polar covalent bonds occur when there is a moderate difference in electronegativity, resulting in an unequal sharing of electrons.
• Ionic bonds are formed when there is a significant difference in electronegativity, causing one atom to donate an electron to another.

The nature of the bond affects the properties of the resulting compounds, such as their solubility, melting and boiling points, and electrical conductivity.

Halogens

Halogens are a group of elements located in Group 17 of the periodic table, which includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are highly reactive and are known for their high electronegativities, particularly fluorine.

• Halogens tend to gain electrons to achieve a stable electron configuration similar to that of noble gases.
• Their high electronegativity makes them very effective at forming ions and engaging in chemical bonds, especially ionic bonds with metals.

Among all the halogens, fluorine is the most electronegative, making it the most reactive of the group. This reactivity is why halogens are found in nature usually combined with other elements rather than as pure substances.