Question

Give the name for each of the following compounds containing a semimetal. (Hint: Name the formula as a binary molecular compound.) (a) \(\mathrm{BF}_{3}\) (b) \(\mathrm{SiCl}_{4}\) (c) \(\mathrm{As}_{2} \mathrm{O}_{5}\) (d) \(\mathrm{Sb}_{2} \mathrm{O}_{3}\)

Short answer

(a) Boron trifluoride; (b) Silicon tetrachloride; (c) Diarsenic pentoxide; (d) Diantimony trioxide.

Step-by-step solution

Understand the Naming Rules for Binary Molecular Compounds

Binary molecular compounds consist of two nonmetals or a semimetal and a nonmetal. They are named using prefixes to denote the number of each element present. These prefixes are: mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6), hepta- (7), octa- (8), nona- (9), and deca- (10). The first element in the formula retains its element name, and the second element's name ends with -ide.

Name the Compound \\ \( \mathrm{BF}_3 \)

The compound \ \( \mathrm{BF}_3 \) consists of boron (a semimetal) and fluorine. Boron does not need a prefix as it is the first element, and there is only one atom. Since there are three fluorine atoms, use the prefix 'tri-' for fluorine, resulting in the name boron trifluoride.

Name the Compound \\ \( \mathrm{SiCl}_4 \)

The compound \ \( \mathrm{SiCl}_4 \) consists of silicon (a semimetal) and chlorine. Silicon does not need a prefix since there's only one atom, and it's the first element. The prefix for four chlorine atoms is 'tetra-,' leading to the name silicon tetrachloride.

Name the Compound \\ \( \mathrm{As}_2 \mathrm{O}_5 \)

The compound \ \( \mathrm{As}_2 \mathrm{O}_5 \) consists of arsenic (a semimetal) and oxygen. The prefix 'di-' is used for two arsenic atoms. For five oxygen atoms, use the prefix 'penta-,' resulting in the name diarsenic pentoxide.

Name the Compound \\ \( \mathrm{Sb}_2 \mathrm{O}_3 \)

The compound \ \( \mathrm{Sb}_2 \mathrm{O}_3 \) consists of antimony (a semimetal) and oxygen. The prefix 'di-' is used for two antimony atoms. For three oxygen atoms, use the prefix 'tri-,' leading to the name diantimony trioxide.

Key concepts

Binary Molecular Compounds

Binary molecular compounds are formed when two different elements combine, and usually, this involves two nonmetals or a semimetal with a nonmetal. Such compounds include combinations like boron with fluorine, silicon with chlorine, arsenic with oxygen, and antimony with oxygen. The naming of these compounds utilizes specific prefixes that indicate the number of atoms of each element present in the compound. This method of nomenclature provides clarity about the composition of a material.
Understanding this concept is crucial for distinguishing between types of compounds and appropriately identifying the structure and formula associated with a specific set of elements.

• These compounds are usually named by placing the name of the first element, followed by the modified name of the second element, ending with "-ide."
• The key to transforming chemical formulas into their respective names lies in the clever use of prefixes indicating the quantity of each atom.

Semimetals

Semimetals, also known as metalloids, have properties that are intermediate between metals and nonmetals. In the context of chemical nomenclature, semimetals, like boron, silicon, arsenic, and antimony, often interact with nonmetals to form binary molecular compounds.
Recognizing semimetals is essential as they are pivotal in many chemical structures and have unique behaviors. Their intermediate nature allows them to form stable compounds with nonmetals, which are essential in various scientific and industrial processes.

• Semimetals are typically less conductive than metals but more so than nonmetals, which affects their chemical bonding.
• Due to their unique position on the periodic table, they can display various chemical behaviors making them versatile candidates in compound formation.

Chemical Prefixes

Chemical prefixes are crucial in naming and identifying the quantity of each element in binary molecular compounds. By using these prefixes, chemists can efficiently communicate the exact composition of a compound without ambiguity. Each prefix represents a specific number of atoms.
Understanding and memorizing these prefixes is fundamental for accurate communication of chemical compositions in both spoken and written forms.

• Common prefixes include mono- (1), di- (2), tri- (3), tetra- (4), and so on up to deca- (10).
• Prefixes are essential for disambiguating different compounds that contain the same elements but in different proportions, such as distinguishing between CO (carbon monoxide) and CO extsubscript{2} (carbon dioxide).