Question

Write the formulas and names of the oxides of the second-period elements (Li to \(\mathrm{N}\) ). Identify the oxides as acidic, basic, or amphoteric. Use the highest oxidation state of each element.

Short answer

Li₂O is basic, BeO is amphoteric, B₂O₃, CO₂, and N₂O₅ are acidic oxides.

Step-by-step solution

Identify Elements and Oxidation States

The second-period elements from Li to N are Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), and Nitrogen (N). We need to use the highest oxidation state for each element, which corresponds to the group number in many cases: Li (+1), Be (+2), B (+3), C (+4), and N (+5).

Write Formulas of the Oxides

Using the highest oxidation states, we determine the formulas of the oxides by balancing the charges between the cations and oxygen. The formulas are: 1. Lithium oxide: Li₂O (Li⁺, O²⁻) 2. Beryllium oxide: BeO (Be²⁺, O²⁻) 3. Boron oxide: B₂O₃ (B³⁺, O²⁻) 4. Carbon dioxide: CO₂ (C⁴⁺, O²⁻) 5. Dinitrogen pentoxide: N₂O₅ (N⁵⁺, O²⁻).

Classify Oxides as Acidic, Basic, or Amphoteric

Classify each oxide based on its nature: 1. Li₂O: Basic, as it reacts with water to form a base (LiOH). 2. BeO: Amphoteric, as it can react with both acids and bases. 3. B₂O₃: Acidic, as it can react with water to form an acid (H₃BO₃). 4. CO₂: Acidic, as it forms carbonic acid (H₂CO₃) when dissolved in water. 5. N₂O₅: Acidic, as it forms nitric acid (HNO₃) in water.

Key concepts

Elemental Oxidation States

Understanding the concept of oxidation states is crucial. They represent the charge an atom would have if all bonds were ionic. For second-period elements like Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), and Nitrogen (N), the highest oxidation state often correlates with their group number on the periodic table:

• Li is in Group 1, so it has an oxidation state of +1.
• Be is in Group 2, thus its oxidation state is +2.
• B is in Group 13, with an oxidation state of +3.
• C is in Group 14, giving it an oxidation state of +4.
• N is in Group 15, resulting in an oxidation state of +5.

This knowledge helps determine the number of electrons involved in forming bonds with oxygen, impacting the chemistry of the compounds they form.

Chemical Formulas

Chemical formulas represent the composition of a compound in terms of the symbols of the elements present and their relative proportions. For oxides of second-period elements, these formulas are determined based on their oxidation states and those of oxygen (which is -2). The goal is to balance the total positive and negative charges. Here are the formulas for the oxides:

• Lithium oxide: Li₂O, where two Li⁺ ions balance one O²⁻ ion.
• Beryllium oxide: BeO, where one Be²⁺ ion balances one O²⁻ ion.
• Boron oxide: B₂O₃, where two B³⁺ ions balance three O²⁻ ions.
• Carbon dioxide: CO₂, where one C⁴⁺ ion is balanced by two O²⁻ ions.
• Dinitrogen pentoxide: N₂O₅, where two N⁵⁺ ions balance five O²⁻ ions.

These formulas provide insight into their molecular composition and potential reactions.

Acidic, Basic, and Amphoteric Oxides

The nature of oxides can be acidic, basic, or amphoteric. This classification depends on how they react with water or other chemicals, forming acids, bases, or both. Let's see how the oxides of second-period elements are classified:

• Basic Oxide: Li₂O is basic because it reacts with water to form LiOH, a strong base.
• Amphoteric Oxide: BeO can react with both acids and bases, showcasing its amphoteric nature.
• Acidic Oxides:
  • B₂O₃ reacts with water to yield boric acid, H₃BO₃, displaying acidity.
  • CO₂ reacts with water to form carbonic acid, H₂CO₃.
  • N₂O₅ dissolves in water to give nitric acid, HNO₃.

Understanding these properties helps predict the behavior of these oxides in various chemical reactions.

Second-Period Elements

The second-period elements span from Lithium (Li) to Neon (Ne) on the periodic table. These elements' properties change significantly across the period due to increasing atomic numbers. For oxides, we're primarily interested in elements Li to N:

• These elements show a diversity of chemical reactions and bonding patterns.
• Their oxides provide a wide range of acid-base characteristics.
• The increasing electronegativity across the period influences their oxidative behavior.

Studying these elements helps us understand broader periodic trends and the complex nature of their chemical compounds.

Oxides Classification

Classifying oxides is essential in understanding their chemical behavior and potential applications. Oxides can be categorized broadly into three types based on their acid-base characteristics:

• Acidic Oxides: These react with water, forming acids. They are typically non-metal oxides, like CO₂ and N₂O₅.
• Basic Oxides: These form bases upon reacting with water. Metal oxides such as Li₂O fall into this category.
• Amphoteric Oxides: These react with both acids and bases. BeO exemplifies this dual behavior.

This classification is pivotal because it aids chemists in predicting how a particular oxide will react under different chemical conditions. Understanding oxide classification informs everything from environmental science to industrial chemistry.