Which group two element is likely to have a similar electronegativity to aluminum?
This question is asking about group two elements, in other words, the elements in the second column of the periodic table. These elements are beryllium, magnesium, calcium, strontium, barium, and radium. The other element mentioned in the question, aluminum, is found in group 13, one element after magnesium.
This question asks us to compare electronegativities. Electronegativity is defined as the tendency of an atom to attract a bonding pair of electrons. To compare the electronegativities of these elements, we need to know the periodic trends of electronegativity. In other words, how does electronegativity increase or decrease as we move side to side or up and down on the periodic table? The horizontal trend is that electronegativity increases as we move to the right in the periodic table.
The reason for this is that atoms with nearly full electron shells tend to attract electrons, in order to fill up that electron shell. Flourine with seven valence electrons has a high electronegativity. Lithium with only one valence electron is much more likely to give up that electron than it is to attract new electrons. In other words, it has a low electronegativity. So we can see as we add valence electrons moving to the right on the periodic table, electronegativity increases.
Next, let’s take a look at the vertical trend. Electronegativity increases as we move up a group in the periodic table. Elements further up on the periodic table have fewer electron shells. When there are fewer electron shells, the bonding pair of electrons that the atom interacts with is closer to the nucleus. For elements further up in a group on the periodic table, since the nucleus and the bonding pair of electrons are closer together, there’s a stronger attraction between them, in other words, a higher electronegativity.
Now that we know the trends, we can begin to compare the electronegativities of these elements. One observation we can make is that aluminum is immediately to the right of magnesium on the periodic table. Since electronegativity increases as we move to the right, one conclusion we can draw from this is that aluminum has a slightly higher electronegativity than magnesium. Can we make a related conclusion, looking at the vertical direction? Since electronegativity increases as we move up a group, we can also say that beryllium has a slightly higher electronegativity than magnesium.
This question is asking us to find the element that has a similar electronegativity to aluminum. Since beryllium and aluminum both have a slightly higher electronegativity than magnesium, they’re likely to have a similar electronegativity to one another. Therefore, we can write in beryllium, the correct answer.
As we’ve just discussed, magnesium has a lower electronegativity than both beryllium and aluminum. The other group two elements below magnesium on the periodic table have even lower electronegativity values and therefore are even less similar to aluminum in that regard. So, “Which group two element is likely to have a similar electronegativity to aluminum?” That’s beryllium.