This lesson will focus on Alkali Earth Metals and Transition Metals.

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Alkali Earth Metals

Alkali Earth Metals, also known as group 2 elements, are unique in their properties. Unlike group 1 elements, they are harder, meaning they cannot be cut by a knife. They are denser than both water and group 1 elements. While they are slippery and shiny, they are not as shiny as group 1 elements.

When it comes to reactivity, Alkali Earth Metals react slowly with water, making them less reactive than group 1 elements. This reactivity, however, increases down the group. This trend is also seen in the reactivity series of metals, where group 1 elements are followed by group 2 elements and then group 3 elements.

In terms of density, it increases down the group. This is because as you go down the group, the mass gradually increases. Given that density is equal to mass divided by volume (), it means that density and mass are directly proportional.

Alkali Earth Metals are also harder than group 1 elements and cannot be cut by a knife. However, their hardness decreases down the group, just like group 1 elements.

One important characteristic of group 2 elements is that their salts are white in color. Examples include lime (calcium oxide or calcium hydroxide), barium sulfate, chalk (calcium carbonate), and limestone.

Transition Metals

Transition Metals are relatively unreactive, especially when compared to other metals. This unreactivity makes them useful as catalysts in various chemical processes. For instance, iron is used as a catalyst in the Haber process for the manufacture of ammonia, and platinum is used in the manufacture of nitrogen dioxide from ammonia.

Transition Metals are also harder and stronger than both group 1 and group 2 elements. This is why iron, a transition metal, is used in bridges, machinery, car parts, and garden tools.

Another unique characteristic of Transition Metals is that their salts are colored. For example, the salts of iron two are green, iron three are brown, and copper two and chromium three are blue.

Most Transition Metals also have a variable valency, meaning they can exhibit more than one oxidation state. For instance, iron can exist in either the iron two or iron three state.

Transition Metals also have higher fixed points (melting and boiling points) compared to group 1 and group 2 elements.

In conclusion, understanding the properties of Alkali Earth Metals and Transition Metals allows us to appreciate their roles and applications in various fields. In the next lesson, we will explore the chemistry of halogens and noble gases.