Chromium-3 Cyanide and Cyanide Ion Concepts

The video tutorial explains how to write the chemical formula for chromium-3 cyanide. It begins by identifying the element symbol for chromium and the charge indicated by the Roman numeral III. The tutorial then describes the cyanide ion, a polyatomic ion with a negative charge, and explains how to balance the charges to achieve a neutral compound. The final formula for chromium-3 cyanide is presented as Cr(CN)3, with a brief conclusion by Dr. B.

What does the Roman numeral III indicate in Chromium-3 Cyanide?

• The number of cyanide ions

• The number of electrons in chromium

• The charge of the chromium ion

• The atomic number of chromium

Which of the following is true about the cyanide ion?

• It is a monatomic ion

• It has a positive charge

• It is a polyatomic ion

• It is found on the periodic table

How can you determine the charge of the cyanide ion?

• By looking it up on the periodic table

• By memorizing it or using a polyatomic ion table

• By calculating the atomic mass

• By counting the number of atoms in the ion

Why do we need to balance the charges in Chromium-3 Cyanide?

• To increase the compound's reactivity

• To stabilize the chromium ion

• To ensure the compound is neutral

• To make the compound soluble

What is the final formula for Chromium-3 Cyanide?

• Cr3CN

• Cr(CN)3

• Cr(CN)2

• CrCN

Why are parentheses used around the cyanide ion in the formula?

• To indicate multiple ions are present

• To show the ion is neutral

• To highlight the ion's charge

• To separate it from the chromium ion