Before we have the activity series chart, so let's take a quick look at it. Realize first that as we go up, the activity series strength increases. And we need to realize here that this first group in red, lithium, potassium, barium, strontium, calcium, sodium, they're above all the other groups, so they can displace any of those. And within that group, since lithium is the highest, it can displace any of the elements below it.
So remember we set the higher up you are in terms of the activity series chart, the easier it is for you to displace the elements below you. We also realize here that we have hydrogen gas kind of as like a border that helps to separate these. Below this border we have these elements here which cannot really displace hydrogen. So if hydrogen is connected to another element, they won't be able to kick out the hydrogen and bond with that other element.
Now here we can talk about what these other groups can do. How can they displace H2? So basically they can replace hydrogen for the first group if it's in the form of liquid water. If it's in the form of gas, well, not liquid gas, water vapor, which we call steam. And then finally if it's in the form of an acid as H3O+. OK, so they can displace hydrogen from any of these forms. They can also displace elements below them.
And as we go down, we see that the activity strength is decreasing. So these could only displace hydrogen if it's found in liquid water or if it's found in gaseous vapor. And then as you can see, we're just going down, down, down what they're able to do. These could only displace it from H3O+, which is our acid. So just remember, we're going to be looking at these elements in their activity series to see how they can displace another element.