Ionic Compounds and Polyatomic Ions

The video tutorial explains how to write the formula for rubidium hydroxide. It begins by identifying rubidium as 'Rb' and introduces hydroxide as a polyatomic ion 'OH-' with a one-minus charge. The tutorial discusses the formation of an ionic compound by combining rubidium, which has a one-plus charge, with hydroxide. It emphasizes the need for the charges to balance to form a neutral compound, resulting in the formula RbOH.

What is the element symbol for rubidium?

• Re

• Ru

• Rb

• Rh

Which of the following is a polyatomic ion?

• O2

• Cl-

• OH-

• H2O

What is the ionic charge of rubidium in rubidium hydroxide?

• 1-

• 2+

• 2-

• 1+

What is the charge of the hydroxide ion?

• 1-

• 2-

• 1+

• 2+

Why must the charges in rubidium hydroxide add up to zero?

• To ensure it is a neutral compound

• To make it reactive

• To make it a stable compound

• To balance the equation

What is the correct formula for rubidium hydroxide?

• Rb(OH)2

• RbO

• RbOH

• RbH