Each of the following pairs of elements will react to form a binary ionic compound. Write the formula of each compound formed, and give its name. (a) Sodium and iodine

Verified step by step guidance

1. Identify the charges of the ions formed by each element. Sodium (Na) typically forms a +1 cation (Na+), and iodine (I) typically forms a -1 anion (I-).
2. Combine the ions in a ratio that results in a neutral compound. Since both ions have charges of equal magnitude but opposite signs (+1 for Na and -1 for I), they will combine in a 1:1 ratio.
3. Write the chemical formula by placing the cation first followed by the anion. In this case, the formula is NaI.
4. Determine the systematic name of the compound. The name of the cation (sodium) is followed by the name of the anion (iodide), resulting in the name sodium iodide.
5. Check the correctness of the formula and name by ensuring the compound is electrically neutral and the names are based on the respective ions.

Key Concepts

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of positively charged cations and negatively charged anions. These oppositely charged ions attract each other, creating a stable compound. The formula of an ionic compound reflects the ratio of the ions involved, ensuring that the overall charge is neutral.

Nomenclature of Ionic Compounds

The naming of ionic compounds follows specific rules. The cation (positive ion) is named first, followed by the anion (negative ion). For monatomic ions, the name of the anion is derived from the element's name, typically by adding the suffix '-ide' to the root. For example, sodium (Na) and iodine (I) combine to form sodium iodide.

Electron Configuration and Reactivity

The reactivity of elements is largely determined by their electron configuration, particularly the number of valence electrons. Sodium, with one valence electron, readily loses it to achieve a stable electron configuration, while iodine, with seven valence electrons, gains an electron to complete its octet. This electron transfer is fundamental in the formation of ionic bonds.