Understanding Ionic Compounds: Cobalt and Sulfur

The video tutorial explains how to name an ionic compound involving cobalt and sulfur. It begins by identifying cobalt as a d-block element, which can have multiple charges, and sulfur as an anion forming sulfide with a 2- charge. The tutorial demonstrates how to balance the charges between cobalt and sulfide ions, resulting in the compound cobalt(III) sulfide. The video also discusses the importance of indicating the charge of polyvalent metals like cobalt in the compound's name using Roman numerals.

What is the primary goal of the video tutorial?

• To name an ionic compound

• To describe the properties of noble gases

• To explain the periodic table

• To discuss chemical reactions

Why are d-block elements like cobalt considered tricky?

• They do not form compounds

• Their ionization is unpredictable

• They are non-metals

• They have a fixed charge

What charge does sulfur typically gain when it becomes an anion?

• 0

• 3+

• 2-

• 1+

How many electrons does sulfur gain to achieve a noble gas configuration?

• One

• Three

• Two

• Four

What is the total negative charge contributed by the sulfide ions in the compound?

• 2-

• 6-

• 4-

• 8-

How many cobalt ions are needed to balance the charge of three sulfide ions?

• Three

• One

• Four

• Two

What is the charge on each cobalt ion in the compound?

• 4+

• 1+

• 2+

• 3+

What is the correct name for the compound formed by cobalt and sulfur?

• Cobalt sulfide

• Cobalt(IV) sulfide

• Cobalt(II) sulfide

• Cobalt(III) sulfide

Why is it necessary to use Roman numerals in the name of the compound?

• To denote the compound's state

• To specify the type of bond

• To show the charge of the cation

• To indicate the number of atoms

What term describes elements like cobalt that can have multiple charges?

• Univalent

• Nonvalent

• Polyvalent

• Monovalent