Why do elements within a group (family or column) in the Periodic Table exhibit similar chemical behavior?
A They all have the same number of protons.
B Within a group, the atoms are the same size.
C The number of electrons in their outermost shells is the same.
D All of the above.
D?
No. Write (or look up the electron configuration) for say the group I elements.
You KNOW it can't be a because every element has a different number of protons. That also tells you it can't be D. You KNOW elements are not the same size so it can't be B.
Yes, the correct answer is D - all of the above.
Elements within a group in the periodic table exhibit similar chemical behavior because they have the same number of valence electrons. Valence electrons are the outermost electrons in an atom, and they are responsible for the atom's chemical properties and behavior.
Option A: Elements in the same group/family have the same number of protons, which determines their atomic number and therefore their identity as an element. However, it is the number of valence electrons that primarily determines their chemical behavior.
Option B: Within a group, atoms may have different sizes due to variations in their atomic radii, but their outermost electron shells (where valence electrons are located) tend to be of similar size.
Option C: The number of valence electrons in the outermost shell is the same for elements within the same group. This similarity in the number of valence electrons leads to similar chemical behavior, as elements with the same number of valence electrons often have similar reactivity and form similar types of chemical bonds.
Therefore, it is the combination of these factors - the same number of protons, similar size of electron shells, and same number of valence electrons - that leads to elements within a group exhibiting similar chemical behavior.