Question

Write the name and formula for the compound formed from sodium ions and nitrite ions.

Short answer

The compound formed from sodium ions (Na+) and nitrite ions (NO2-) is sodium nitrite with the formula \(NaNO_2\).

Step-by-step solution

Identify the ions

Sodium ions have a +1 charge and are represented by Na+. Nitrite ions have a -1 charge and are represented by NO2-.

Combine the ions to form a compound

In neutral compounds, the total charge should be zero. Since the charges on both ions are equal and opposite, they balance each other. Therefore, we can combine one sodium ion (Na+) and one nitrite ion (NO2-) to form a compound.

Write the formula for the compound

Writing the representative elements and their proportions (in this case 1:1), we get the formula for the compound: \(NaNO_2\).

Name the compound

The compound formed from sodium ions and nitrite ions is called sodium nitrite.

Key concepts

Chemical Nomenclature

Understanding chemical nomenclature is crucial for identifying and working with chemical compounds. This is the standardized way by which scientists name various chemical substances. The name reveals the chemistry and, often, the structure of the substance.

In the context of our sodium nitrite example, the name tells us that the compound consists of sodium (Na) and nitrite (NO2) ions. The nomenclature rules determine that we write the name of the metal ion (sodium) first followed by the name of the non-metal ion (nitrite), which derives from nitrogen dioxide (NO2) with one oxygen less.

When writing chemical formulas, you should balance the charges of ions so that the overall charge of the compound is neutral. In our exercise, because sodium has a +1 charge and nitrite has a -1 charge, they combine in a 1:1 ratio to form a neutral compound, resulting in the formula \(NaNO_2\).

Ionic Bonding

The formation of sodium nitrite illustrates the process of ionic bonding. This type of chemical bond is a result of the electrostatic attraction between oppositely charged ions.

Atoms achieve a more stable arrangement by either losing or gaining electrons to obtain a full valence shell, similar to the nearest noble gas configuration. Metals like sodium tend to lose electrons and form positively charged ions or cations. Non-metals, in some cases like the polyatomic nitrite ion, gain electrons to form negatively charged ions or anions.

In our example, a sodium atom loses one electron becoming a Na+ ion, while the nitrite ion carries an extra electron, represented as NO2-. These ions then attract each other and form an ionic bond, resulting in the compound \(NaNO_2\).

Polyatomic Ions

A polyatomic ion is a charged particle which consists of two or more covalently bonded atoms, or of a metal complex that can be considered to be acting as a single unit.

The nitrite ion (NO2-) is an example of a polyatomic ion. It behaves as a single unit in chemical reactions, despite being composed of one nitrogen and two oxygen atoms. Unlike simple ions like sodium (Na+), which consist of a single element, polyatomic ions have a specific internal structure that must stay intact during chemical reactions.

When combining with other ions, such as with sodium to form sodium nitrite, the polyatomic ion's entire group acts as one part of the compound. It's crucial to note that while sodium is represented in formulas by its elemental symbol, 'Na', the nitrite ion is represented by its molecular formula, 'NO2', with a charge of -1.