Elements in the same block show similar behaviours. For example, all the non-metals are in the p-Block and all the reactive metals are within the s-Block.
The elements in the same group show more specific similarities, for example group two contain similar properties, as was investigated previously.
Horizontal rows are called periods. There are few similarities in the elements across the periods. However there are trends that are common to each period.
Elements change from metallic to non-metallic across a period, and become more metallic, or more non-metallic down a group.
Physical properties of the periodic table
The arrangement of the periodic table is in order of atomic number.
As you move along the table, the atomic radius of the elements decrease; this is because the electron shells are within the same energy level, but there re more protons as you move along the group, so the pull on the electrons is stronger, making the radius decrease.
There is a periodic trend in the first ionisation energy required. The energy increases up to group eight, due to the extra protons for the same period, it then decreases as you go back to group one, because there is one extra energy level, meaning the electrons are further away from the proton, and there is more shielding of the positive charge of the nuclues.
Below is the graph showing the melting point across the periods within the periodic table. Notice the peaks which correspond to the group 4 elements. This is called a periodic trend.