Cobalt and Phosphide Compounds

The video tutorial explains how to write the formula for cobalt three phosphate by identifying the element symbols and balancing the charges between cobalt and phosphorus. It further discusses the neutrality of cobalt three phosphide and how to name the compound from its formula, emphasizing the use of Roman numerals to indicate the charge of transition metals.

What is the element symbol for cobalt?

• Ct

• Cl

• Cb

• Co

What does the Roman numeral III indicate in cobalt(III) phosphate?

• The number of cobalt atoms

• The charge of cobalt

• The atomic number of cobalt

• The number of phosphate ions

What is the charge of the phosphide ion?

• 2-

• 1+

• 3+

• 3-

How do the charges of cobalt and phosphide ions result in a neutral compound?

• They both have a charge of 3-

• They both have a charge of 3+

• Cobalt is 3+ and phosphide is 3-

• Cobalt is 2+ and phosphide is 2-

If given the formula CoP, what would be the charge of cobalt?

• 4+

• 3+

• 2+

• 1+

How is the Roman numeral III used in naming cobalt(III) phosphide?

• It represents the number of cobalt atoms

• It denotes the atomic mass of cobalt

• It shows the charge of cobalt

• It indicates the number of phosphorus atoms