Question

carbon and chlorine form a covalent compound whose formula is ccl₄. the name of this compound is
carbon (iv) chloride
carbon chloride
monocarbon tetrachlorine
carbon tetrachloride
question 21
100 pts
which of the following pairs of names and symbols is correct?
phosphorus tetrachloride, pcl₃
nitrogen dioxide, no₂
phosphorus heptachloride, pcl₇
monosilicon tetrafluoride, sif₄

Explanation:

For the first question:

• In naming covalent compounds, the prefixes indicate the number of atoms. The formula \(CCl_4\) has one carbon (\(C\)) and four chlorine (\(Cl\)) atoms. The prefix for four is "tetra -", and the ending of the second element (chlorine) is changed to "-ide". So it is carbon tetrachloride.
• "Carbon (IV) Chloride" is an incorrect naming convention for covalent compounds (this naming style is more for ionic compounds with transition metals showing variable oxidation states). "Carbon Chloride" doesn't account for the number of chlorine atoms. "Mono carbon Tetra chlorine" has incorrect prefix - element combination (prefixes are for the number of atoms of each element, and the second element should have - ide ending).

For the second question:

• For "phosphorus tetrachloride", the formula should be \(PCl_4\) (tetra - means four), but the given formula is \(PCl_3\) (which would be phosphorus trichloride).
• "nitrogen dioxide" has the formula \(NO_2\) (di - means two oxygen atoms), which is correct.
• "phosphorus heptachloride" should have the formula \(PCl_7\), but phosphorus typically doesn't form \(PCl_7\) (common chlorides of phosphorus are \(PCl_3\) and \(PCl_5\)).
• "monosilicon tetrafluoride" is incorrect. The compound \(SiF_4\) is named silicon tetrafluoride (mono - is not used when there is only one atom of the first element in covalent compound naming if it is the first element in the formula and there is no ambiguity).

Answer:

First question: Carbon Tetrachloride
Second question: nitrogen dioxide, \(NO_2\)