Question

Give the proper formula for each name. a) nitrogen triiodide b) diarsenic trisulfide c) iodine trichloride

Short answer

a) \( \text{NI}_3 \); b) \( \text{As}_2\text{S}_3 \); c) \( \text{ICl}_3 \).

Step-by-step solution

Determine the Elements and their Prefixes for Nitrogen Triiodide

The name "nitrogen triiodide" indicates the presence of nitrogen and iodine. The prefix "tri" means three. Thus, nitrogen triiodide is composed of one nitrogen atom and three iodine atoms. The chemical symbol for nitrogen is "N" and for iodine is "I".

Write the Formula for Nitrogen Triiodide

Using the information from Step 1, the formula for nitrogen triiodide is written as \( \text{NI}_3 \). This represents one nitrogen atom bonded with three iodine atoms.

Determine the Elements and their Prefixes for Diarsenic Trisulfide

The name "diarsenic trisulfide" indicates the presence of arsenic and sulfur. The prefix "di" means two, and "tri" means three. Hence, diarsenic trisulfide consists of two arsenic atoms and three sulfur atoms. The chemical symbol for arsenic is "As" and for sulfur is "S".

Write the Formula for Diarsenic Trisulfide

Utilizing the prefixes, the formula for diarsenic trisulfide is \( \text{As}_2\text{S}_3 \). This represents two arsenic atoms combined with three sulfur atoms.

Determine the Elements and their Prefixes for Iodine Trichloride

For "iodine trichloride," the elements are iodine and chlorine. The prefix "tri" means three. Therefore, iodine trichloride consists of one iodine atom and three chlorine atoms. The symbols for iodine and chlorine are "I" and "Cl" respectively.

Write the Formula for Iodine Trichloride

Based on Step 5, the formula for iodine trichloride is \( \text{ICl}_3 \). This indicates one iodine atom bonded with three chlorine atoms.

Key concepts

Molecular Compounds

Molecular compounds are formed when two or more nonmetal elements are chemically bonded together. This is distinct from ionic compounds, which typically involve a metal and a nonmetal. In molecular compounds, elements share electrons to achieve stability, creating what are known as covalent bonds.
Understanding these bonds can help you predict and understand the properties of the compound. Some important features of molecular compounds include:

• They often have lower melting and boiling points compared to ionic compounds.
• Molecular compounds do not conduct electricity in solid or liquid form.
• They are usually gases or liquids at room temperature.

A perfect example would be water (H₂O) or carbon dioxide ( CO₂). These compounds demonstrate how different elements can come together to form new substances with unique properties. Naming molecular compounds involves using prefixes that denote the number of atoms of each element present in the compound. This allows you to easily determine the composition of the compound at a glance, which is particularly helpful in the field of chemistry.

Chemical Formulas

Chemical formulas represent the composition of a chemical substance using element symbols and numerical subscripts. It's a shorthand way of expressing how many atoms of each element are present in a compound. For instance, the chemical formula for water is H₂O, indicating it has two hydrogen atoms and one oxygen atom.
The formula is important because it gives insight into the numerical proportions and types of atoms involved in the chemical compound. When creating chemical formulas for molecular compounds, it's important to use the correct prefixes, as seen in the exercise solution. For example:

• The prefix 'mono-' indicates one atom, though it's usually omitted for the first element mentioned.
• The prefix 'di-' indicates two atoms.
• The prefix 'tri-' indicates three atoms.

Using these rules helps ensure the accuracy of the chemical formula. Incorrect formulas can lead to misunderstandings about the chemical structure and properties of the compound, which is why it's crucial to get them right! Another point to note is that chemical formulas often reflect the simplest ratio of the compound's components, providing a quick reference point for chemists.

Element Symbols

Element symbols are the abbreviated forms of the names of elements that are generally one or two letters long. Using these symbols simplifies written chemical equations and formulas, making them easier to read and understand. Every element has a unique symbol, usually derived from its English or Latin name. For example, the element symbol for nitrogen is 'N', while iodine's symbol is 'I'. Using these symbols is essential in chemistry for clear communication.
These standardized symbols help avoid confusion that may arise from language differences and long chemical names. It's important to learn and remember these symbols, as they are frequently used in writing chemical equations and formulas. To delve deeper:

• Single-letter symbols, like H for hydrogen, are capitalized.
• Two-letter symbols have the first letter capitalized and the second letter in lowercase, like Co for cobalt.

Knowing element symbols is foundational for anyone studying chemistry, as it sets the stage for understanding more complex concepts like molecular formulas and chemical reactions. It also aids in efficient communication among chemists globally.