Question

What is the electronegativity trend? Where does hydrogen fit into the electronegativity trend for the other elements in the periodic table?

Short answer

The electronegativity trend in the periodic table is characterized by an increase from left to right across a period and a decrease from top to bottom within a group. Hydrogen, with an electronegativity value of 2.20 on the Pauling scale, does not follow the usual trends observed in the periodic table. Although located in Group 1, its electronegativity is higher than any other element within this group, placing it closer to the values of nonmetals in the upper-right portion of the periodic table.

Step-by-step solution

Define electronegativity

Electronegativity is a measure of an atom's ability to attract shared electrons in a chemical bond. It is an important concept in chemistry because it helps predict which atoms will participate in chemical reactions, and what types of bonds will form between them.

Explain the electronegativity trend in the periodic table

The electronegativity trend in the periodic table can be explained as follows: - Electronegativity generally increases from left to right across a period. This is because as you move across a period, the number of protons in the nucleus increases, increasing the positive charge and therefore the force of attraction for electrons. - Electronegativity generally decreases from top to bottom within a group. As you move down a group, the atomic radius increases due to the additional energy levels, causing the outer electrons to be further away from the nucleus. This results in a weaker force of attraction for the outer electrons and thus a lower electronegativity.

Determine the position of hydrogen within the trend

Hydrogen is an exception to the general trends in the periodic table. It does not have a specific trend as other elements do, but it is essential to discuss hydrogen's electronegativity to compare it with the other elements. Hydrogen is located in the first group (Group 1) and the first period (Period 1) and has an electronegativity value of 2.20 (on the Pauling scale). Although hydrogen is placed within Group 1, it does not follow Group 1's trend of decreasing electronegativity down the group. Typically, alkali metals in Group 1 have low electronegativity values (due to having only one electron in their outer orbital, making them want to lose it rather than attract). But hydrogen, with an electronegativity of 2.20, is higher than any other element in this group. In conclusion, hydrogen does not follow the usual trends observed within the periodic table. Its electronegativity value places it closer to the values of other nonmetals in the upper-right portion of the periodic table.