Most workshops are there to teach you a skill, or set of skills. While a conference is mostly about passively listening to talks and reading posters, in a workshop you are actively engaged in doing something.

This can be learning a new piece of software, learning a mathematical method, how to use a specific machinery or an instrument, etc. There are also going to be talks about the subject: theory, applications and possible more.

Not all workshops are like that - I've been in a one day "workshop" where all we did was sit in a lecture hall listening to people talk about a common topic. In an ideal workshop you would hopefully be actively doing something.

Also, in conferences you are usually able (and expected) to present something, be it a talk or a poster. In workshop this is rarely the case, and the agenda is predetermined.

What is done in a workshop? How does it differ from an academic conference?
I recently came across a practice problem in my textbook asking me to name a few compounds using -ic and -ous endings. The exact wording is:

Write the name of each of the following ionic substances, using -ous and -ic endings to indicate the charge of the cation.

The first one was CoCl2. However, cobalt has more than just two oxidization states (3, 2, 0, and -1).

So if it is one of the states in the middle, how do I decide whether to use -ous or -ic
