Ions Overview

This link is to a blog which goes through the tests for ions:
http://level2ions.blogspot.co.nz/

CATIONS

This specific post is the one you want for the cation experiments we are doing in class at the moment:
http://level2ions.blogspot.co.nz/2014/09/colourless-cations.html

One key point to note is about Barium, The Flow Chart we are using says that Barium ions do not precipitate out with Hydroxide ions. If the concentration of either is high enough, it does go milky/cloudy. Therefore, it can be confused for Magnesium. If you suspect an ion is Magnesium, test a new sample with sulfuric acid. If it precipitates out, it is really Barium. If nothing happens, it is Magnesium.

ANIONS

If you have any issues distinguishing between the colours of the precipitates, the following Flow Chart is sometimes easier to use. For example, it there is a coloured cation, it is tough to tell exactly what colour the precipitate is.

Coloured Ions

The first (preliminary) test we do on unknown ionic solutions is to see if it has a colour. Some ions have characteristic colours, so we can infer one of the ions present in a coloured solution. We do need to confirm this "hunch" with chemical reactions, but it is a great starting point.

Writing Formulae and Balancing Equations

We started by being reminded of how to write the formulae for ionic compounds and molecules:

Next, we did these simple experiments and used these to practice making observations and to balance chemical equations:

Bonding

Why do atoms bond together? They are already electrically-neutral, so why do some become ions?

With this brief (and quick) overview of bonding, we were given this challenge:

Atomic Structure and Bonding

The Bohr Model is a convenient one for predicting the electron configuration of an atom. From this, we can infer the charge of its ion, or if it can form covalent bonds.

The Periodic Table is arranged in columns called Groups. Elements within the same Group have very similar chemical properties. Chemical properties are determined by the electron configuration. Therefore, even if we do not know the structure of an atom (such as Barium, Ba), we can infer the ion it makes and its properties from the elements in its Group.