Question

Which of the following elements is more likely to form chemical bonds: xenon (Xe) or sodium (Na)? Explain why.

Short answer

Sodium (Na) is more likely to form chemical bonds due to its single valence electron.

Step-by-step solution

Understand Valence Electrons

Sodium (Na) has one valence electron in its outer shell, while xenon (Xe) has a full outer shell with eight valence electrons. Elements form bonds to achieve complete outer electron shells.

Determine Bonding Tendencies

Sodium, with only one valence electron, tends to lose this electron easily to achieve a stable configuration, becoming a positively charged ion (Na⁺). On the other hand, xenon already has a full valence shell, making it very stable and unlikely to form bonds.

Relate to Chemical Reactivity

Chemically reactive elements often have incomplete outer electron shells. Sodium, with its single valence electron, is very reactive and forms bonds readily, while xenon is a noble gas, known for its lack of reactivity due to its complete valence shell.

Key concepts

Valence Electrons

Valence electrons are the electrons found in the outermost shell of an atom, and they play a crucial role in determining how an element behaves chemically. The number of valence electrons can influence an element's ability to form chemical bonds.
Elements tend to bond in ways that allow them to fill or empty their outer electron shell to achieve a stable electronic configuration, often resembling the electron configuration of noble gases. For instance:

• Sodium (Na), with its single valence electron, tends to lose this electron easily.
• Losing the electron helps sodium achieve a stable electron configuration like that of neon, a noble gas.
• Xenon (Xe), however, already has a full outer shell of eight valence electrons, making it stable without having to form bonds.

Therefore, elements with nearly filled or almost empty valence shells are often more reactive, striving to either gain, lose, or share electrons to complete their valence shell.

Chemical Reactivity

Chemical reactivity refers to the tendency of an element to undergo chemical changes. The reactivity of an element is largely determined by its number of valence electrons. Elements that have incomplete outer electron shells are generally more reactive.
Consider sodium (Na) again. It has a single valence electron, which it can lose easily. By doing this, sodium can quickly achieve a stable configuration, similar to noble gases. This tendency to lose an electron makes sodium highly reactive.
In contrast, xenon (Xe), which is part of the noble gas group, possesses a complete valence shell. This full shell makes xenon one of the least reactive elements. Therefore, it seldom participates in chemical reactions. In summary:

• More reactive elements generally have fewer valence electrons to give away or almost a complete set to receive.
  
• Noble gases, like xenon, are known for their lack of reactivity due to already having a complete shell of valence electrons.
  

Understanding the concept of valence electrons helps explain why certain elements are more reactive than others.

Noble Gases

Noble gases are a group of chemical elements with similar properties. They occupy the last column on the right of the periodic table, and they include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
One defining characteristic of noble gases is their full valence electron shell. Most noble gases have eight valence electrons, with the exception of helium which has two, yet this still satisfies the helium's first shell capacity.
Because of their complete electron shells, noble gases are incredibly stable and generally do not form chemical bonds. This full valence shell means they have little interest in gaining or losing electrons.
Notably:

• Noble gases rarely participate in reactions or form compounds under normal conditions.
  
• Their lack of reactivity makes them useful in environments where reactions are unwanted, such as providing non-flammable environments or preserving sensitive materials.
  

Overall, the stable configuration of noble gases offers insight into the reactivity, or rather the lack of it, among these elements.