Question

1. how can you determine if elements have the same chemical properties?

Explanation:

Chemical properties of elements are related to their electron configurations, especially the valence electrons. Elements in the same group (vertical column) of the periodic table have the same number of valence electrons. This similarity in valence - electron configuration leads to similar chemical properties as they tend to react in similar ways to achieve a stable electron configuration (like a full outer shell).

Answer:

Elements that are in the same group (vertical column) of the periodic table have the same number of valence electrons and thus tend to have the same chemical properties.