Question

consider the elements in this family (group) of the periodic table. because they are in the same family, what can you predict about these elements?
a they are all about the same mass.
b they are chemically reactive in a similar way.
c the size of the atom decreases as you go down the column.
d the elements change from metals to nonmetals as go down the column.

Explanation:

• Option A: Elements in the same group have different atomic masses. For example, in the group shown (alkaline - earth metals like \(Sr\), \(Ba\), \(Ra\)), their atomic masses increase as we go down the group.
• Option B: Elements in the same group (family) have the same number of valence electrons. Valence electrons determine chemical reactivity. So, they are chemically reactive in a similar way.
• Option C: As we go down a group, the number of electron shells increases. This leads to an increase in atomic size, not a decrease.
• Option D: The group shown (alkaline - earth metals) consists of only metals. As we go down the group, there is no transition from metals to non - metals.

Answer:

B. They are chemically reactive in a similar way.