Difficulty in Removing Second Electron in Alkali Metals

The removal of the second electron in alkali metals can be considered difficult. This is due to the following reasons:

1. Electron Configuration:
- Alkali metals have a general electron configuration of [noble gas] ns1, where 'n' represents the principal quantum number.
- The first electron is easily removed from the outermost 'ns1' orbital, resulting in a stable noble gas configuration.
- However, the removal of the second electron would require breaking into the stable noble gas configuration, which requires a significant amount of energy.

2. Ionization Energy:
- The energy required to remove an electron from an atom is known as ionization energy.
- The ionization energy generally increases as we move from left to right across a period in the periodic table.
- Alkali metals are located in Group 1, the leftmost group of the periodic table, meaning they have the lowest ionization energies in their respective periods.
- Despite having relatively low ionization energies, the removal of the second electron still requires more energy compared to removing the first electron.

3. Shielding Effect:
- The shielding effect refers to the repulsion between electrons in different energy levels, which reduces the effective nuclear charge experienced by an electron in the outermost energy level.
- In alkali metals, the outermost electron experiences a weaker effective nuclear charge due to the shielding effect of the inner electrons.
- However, as we remove the first electron, the effective nuclear charge experienced by the second electron increases, making it more difficult to remove.

4. Electrostatic Attraction:
- The second electron in alkali metals is held more strongly by the positively charged nucleus compared to the first electron.
- The electrostatic attraction between the negatively charged electron and the positively charged nucleus increases as we move closer to the nucleus.
- Therefore, the second electron experiences a stronger electrostatic attraction, making it more difficult to remove.

Overall, the removal of the second electron in alkali metals can be considered difficult due to factors such as electron configuration, ionization energy, shielding effect, and electrostatic attraction. However, it is important to note that the difficulty in removing the second electron decreases as we move down the alkali metal group, as the atomic radius increases and the effective nuclear charge experienced by the outermost electron decreases.