Naming Binary Molecular Compounds: Videos & Practice Problems

Binary molecular compounds consist of two different nonmetals, such as water (H₂O) and nitrogen oxides (NO). Naming these compounds involves using numerical prefixes: mono (1), di (2), tri (3), tetra (4), penta (5), hexa (6), hepta (7), octa (8), nona (9), and deca (10). The first nonmetal is named normally without "mono," while the second takes the base name, a prefix, and ends in "ide." If a prefix ending in "a" is adjacent to "o," the "a" is dropped, as in "tetroxide" for four oxygens.

Naming Binary Molecular Compounds Concept 1

Binary molecular compounds are formed from two different nonmetal elements. Common examples include water (H₂O), which consists of hydrogen and oxygen, and nitrogen oxides, such as NO (nitric oxide), where nitrogen and oxygen combine. These compounds are characterized by their ability to form in various proportions, necessitating the use of numerical prefixes to indicate the number of atoms of each element present in the compound.

The numerical prefixes used in naming these compounds are as follows: mono- for 1, di- for 2, tri- for 3, tetra- for 4, penta- for 5, hexa- for 6, hepta- for 7, octa- for 8, nona- for 9, and deca- for 10. These prefixes are essential for accurately conveying the composition of the compound, especially when multiple combinations of the same elements can occur.

In summary, binary molecular compounds are covalent compounds made up of two different nonmetals, and the use of numerical prefixes is crucial for their proper naming and understanding of their molecular structure.

Naming Binary Molecular Compounds Concept 2

When naming binary molecular compounds, it is essential to follow specific rules to ensure clarity and accuracy. The first nonmetal in the compound is named using its standard name, accompanied by numerical prefixes to indicate the number of atoms present, except for the prefix "mono," which is never used for the first element. For the second nonmetal, its base name is retained, and it also uses numerical prefixes, but its name must end with the suffix "ide." This indicates that it is part of a binary compound.

Additionally, when a numerical prefix that ends with the letter "a" is adjacent to a prefix that starts with the letter "o," the "a" is typically dropped to avoid awkward pronunciation. For instance, the compound with four oxygen atoms would be referred to as "tetroxide" instead of "tetraoxide," demonstrating this rule in practice.

By adhering to these naming conventions, one can accurately identify and communicate the composition of binary molecular compounds.

Naming Binary Molecular Compounds Example 1

When writing chemical formulas for compounds, it's essential to understand the prefixes that indicate the number of atoms present in each element. For example, in the compound disulfur monochloride, the prefix "di-" signifies two sulfur atoms, leading to the formula S₂Cl. The prefix "mono-" indicates one chlorine atom, which retains its base name.

Next, consider tetraphosphorus pentasylenide. Here, "tetra-" means four, so we have four phosphorus atoms, represented as P₄. The prefix "penta-" indicates five selenium atoms, resulting in the formula P₄Se₅.

Lastly, for dibromoheptoxide, "di-" indicates two bromine atoms, giving us Br₂. The term "hept-" refers to seven, and "oxide" indicates the presence of oxygen, leading to seven oxygen atoms, which results in the formula Br₂O₇.

In summary, when constructing chemical formulas, the first nonmetal retains its name and uses numerical prefixes (except for "mono"), while the second nonmetal also uses numerical prefixes but changes its ending to "-ide." This systematic approach helps in accurately representing the composition of chemical compounds.

Give the systematic name for the following compound:SeF₆

• A. selenium fluoride
• B. selenium hexafluoride
• C. monoselenium hexafluoride
• D. monoselenium fluoride
• E. selenium fluorite

Answer: (B)

Give the systematic name for the following compound:IO₅

• A. iodine oxide
• B. monoiodine oxide
• C. iodine pentoxide
• D. iodide pentoxide
• E. monoiodide pentoxide

Answer: (C)

Give the systematic name for the following compound:N₂S₄

• A. nitrogen tetrasulfide
• B. dinitrogen tetrasulfide
• C. dinitrogen sulfide
• D. nitrogen sulfide
• E. nitrogen sulfite

Answer: (B)

Here’s what students ask on this topic:

What are binary molecular compounds and how are they different from ionic compounds?

Binary molecular compounds consist of two different nonmetals bonded together through covalent bonds, where electrons are shared between atoms. Examples include water (H₂O) and nitrogen dioxide (NO₂). In contrast, ionic compounds are formed between metals and nonmetals, where electrons are transferred from the metal to the nonmetal, creating ions. An example of an ionic compound is sodium chloride (NaCl). The key difference lies in the type of bonding: covalent for molecular compounds and ionic for ionic compounds.

What are the rules for naming binary molecular compounds?

To name binary molecular compounds, follow these rules: 1) The first nonmetal is named normally and uses numerical prefixes except for 'mono'. 2) The second nonmetal keeps its base name, uses any numerical prefix, and ends in 'ide'. 3) If a prefix ending in 'a' is adjacent to 'o', the 'a' is dropped. For example, 'tetraoxide' becomes 'tetroxide'. Numerical prefixes include mono (1), di (2), tri (3), tetra (4), penta (5), hexa (6), hepta (7), octa (8), nona (9), and deca (10).

Why are numerical prefixes important in naming binary molecular compounds?

Numerical prefixes are crucial in naming binary molecular compounds because they indicate the number of atoms of each element in the compound. These compounds can combine in different proportions, leading to different compounds with distinct properties. For example, CO (carbon monoxide) and CO₂ (carbon dioxide) are different compounds with different properties. The prefixes help distinguish between these compounds by specifying the exact number of atoms involved.

How do you name a compound with the formula N₂O₄?

To name the compound N₂O₄, follow the naming rules for binary molecular compounds: 1) The first nonmetal (nitrogen) is named normally with the prefix 'di' for two atoms, becoming 'dinitrogen'. 2) The second nonmetal (oxygen) uses the base name 'oxide' with the prefix 'tetra' for four atoms, becoming 'tetraoxide'. Since 'a' and 'o' are adjacent, drop the 'a'. The name is 'dinitrogen tetroxide'.

What is the significance of dropping the 'a' in prefixes like 'tetra' when naming binary molecular compounds?

Dropping the 'a' in prefixes like 'tetra' when it is adjacent to 'o' in naming binary molecular compounds simplifies pronunciation and avoids awkward combinations of vowels. For example, 'tetraoxide' becomes 'tetroxide'. This rule helps maintain clarity and ease of communication in chemical nomenclature.