Aluminum melts at 660C and iron at 1535C. What can you say about the melting points of the group 1 elements compared to other metals such as these two

Expert Answers
jerichorayel eNotes educator| Certified Educator

Here are the list of the melting points of the group I metals. 

Metal  Melting point (in Kelvin) Boiling point (in Kelvin)

Li          454                                 1615

Na        371                                 1156

K          337                                 1032

Rb        312                                  961

Cs        302                                  944

Fr*       900                                  950


Generally, the melting points of the group I metals are lower compared to other metals in the periodic table. There are certain reasons that can account to this phenomenon. First, group I metals or the alkali metals have only 1 electron in the outer shell that contributes to the "sea of metals" therefore the metallic bonding is weak. Secondly, the group I metals are not as closely packed as compared to the other metals. Consequently, they will have smaller densities and are generally softer. Since the attraction of the metal to each other is weak, not much energy is required to break them thus having a lower melting point.


msmegan | Student

Melting points of elements, along with boiling points as well, rely on the strength of of the particles that make these elements up. 

Because melting points show periodic properties, we can say that elements' melting points vary based on their position in the periodic table. 

Group 1 elements are grouped in such a way that they descend, or go down, on the periodic table.  The reason they go down, or descend, like this is because the forces of attraction between the atoms is gradually getting more weak.  Therefore, because their attraction between the atoms is weaker, the melting point decreases also. 

The attraction between the atoms in Aluminum and Iron are much stronger and therefore have much higher melting points to break these bonds.