why do you think that the electronegativity value for hydrogen is so high given its location in the table?
Hydrogen can lose, or gain an electron. This would put it where you see it, above Li, or above F. On the average then, it can easily loose an electron (low ionization energy) or gain and electron (high electronegativity). The average then for these actions is about 2 on the electronegativity scale (avg between near zero and near 4).
The electronegativity value of an atom gives us an indication of its tendency to attract electrons towards itself in a chemical bond. Hydrogen's high electronegativity value is somewhat surprising considering its location in the periodic table, where it is placed with the alkali metals.
To understand why hydrogen has a relatively high electronegativity value, we need to consider a few factors:
1. Size of the atom: Generally, smaller atoms hold their electrons more tightly due to their proximity to the nucleus. Hydrogen is the smallest atom on the periodic table, consisting of only one electron and one proton. This small size allows hydrogen to have a relatively high electronegativity value, as the electron is closer to the positively charged nucleus.
2. Electron configuration: Hydrogen has an electron configuration of 1s1, meaning it contains only one electron in its outermost shell. This shell is not completely filled, giving hydrogen a stronger pull on electrons compared to atoms with complete electron shells.
3. Ionization energy: Ionization energy is the energy required to remove an electron from an atom. Hydrogen has a relatively high ionization energy, indicating that it strongly holds onto its lone electron. This is reflected in its high electronegativity value.
4. Bonding characteristics: Hydrogen frequently forms polar covalent bonds with more electronegative elements, such as oxygen or fluorine. In these bonds, the electron pair is shared unequally, with hydrogen having a partial positive charge. This further contributes to hydrogen's relatively high electronegativity value.
To calculate electronegativity values, we often refer to different scales such as the Pauling scale or the Mulliken-Jaffe scale. These scales are based on experimental data and trends observed in chemical compounds.
In summary, hydrogen's high electronegativity value can be attributed to its small size, electron configuration, ionization energy, and bonding characteristics. These factors collectively contribute to hydrogen's strong tendency to attract electrons towards itself in a chemical bond.