Specific Groups

Alkali Metals

The alkali metals found in group 1 of the periodic table have extremely low electronegativities and low electron affinities. Due to this they readily form cations with a +1 charge and as a result, have the lowest first ionization energies of the elements.

Due to this property, they are highly reactive and readily form ionic salts with halogens (NaCl) in addition to forming strong bases when combined with hydroxide ions (KOH). Their propensity to form strong bases is why they go by the name alkali metals with alkali originally referring to the wood ash historically used to generate bases such as lime.

Alkaline Earth Metals

The alkaline earth metals are just to the right of the alkali metals in group 2. Since they also have low electronegativities and low electron affinities, they readily form cations as well. However, they need to lose two electrons in order to attain noble gas configuration. As a result, they exist at cations with a 2+ charge and have the lowest second ionization energy of the elements.

Just like alkali metals, they are highly reactive and readily form ionic salts with the halogen (CaCl₂) and strong bases when combined with hydroxide ions (Sr(OH)₂). Again they share the alkali in alkaline because of this propensity.

Transition Metals

Next to the alkaline earth metals are the transition metals spanning from group 3 to group 12. Given their position in the lower middle portion of the periodic table they have low electronegativities and low electron affinities. Despite this, their properties diverge from both the alkali metals and the alkaline earth metals because unlike both groups 1 and 2 they have valence electrons in the d-orbital.

The d-orbital electrons are fluid and sorta come and go as they please. This means that transition metals are not only excellent conductors but have a wide range of different oxidation states. For example, Mn can have an oxidation number of +2, +3, +4, +6, or +7 charge. As a result, the transition metals form a ton of different ionic compounds. Furthermore, the d-orbitals electron transitions correspond to the visible light spectrum. This means that the transition metals form a wide array of colored compounds.

Lastly the transition metals have a propensity to form complexes via coordinate covalent bonds as we will explore later. These are often found as co-factors for enzymes or carriers as the iron is in hemoglobin.

Oxygen Group

The oxygen group is as you guessed is the group that contains oxygen. Also known as the chalcogens they are located in group 16 of the periodic table. They have higher electronegativities and electron affinities, but properties wise tend to be a bit inconsistent. The biggest factor they have in common is their importance in biological organisms specifically metabolism.

Halogens

The halogens are right next to the oxygen group in 17. Of all of the elements they have the highest electronegativities values and electron affinities. Due to this they predominantly as anions with a -1 charge and desperately want to attain noble gas status. This makes them very reactive especially towards group 1 and 2 where they readily form ionic bonds.

Noble Gases

To round out the periodic table we have the noble gases. As nobles, they are fully fulfilled with their lives and their valence shells represent this. This leads them to have near-zero electronegativity and electron affinity values and extremely high ionization energies, making them unreactive or inert.

Using this Information

It is possible that you will be asked to identify the name of a particular group. However, the true value in understanding the different groups comes in recognizing and predicting how an element will behave in reactions. I will point this out as we go and I want you to start identifying any elements you come across in practice problems and thinking about the properties they possess and why they explain what is happening to them in the question or passage.