To determine which atom has the highest ionization energy, we need to consider the periodic trends in the periodic table. Ionization energy is the energy required to remove an electron from an atom in the gas phase. The periodic table trends can help us understand how ionization energy varies among different elements.
1. Periodic Trend Across a Period (Row):
- As you move from left to right across a period, the ionization energy generally increases.
- This is because the atomic number increases, leading to a higher positive charge in the nucleus. This increased positive charge pulls the electrons closer to the nucleus, making them harder to remove.
2. Periodic Trend Down a Group (Column):
- As you move down a group in the periodic table, the ionization energy generally decreases.
- This is because the electrons are being added to higher energy levels further from the nucleus. The increased distance and electron shielding reduce the effective nuclear charge felt by the outermost electrons, making them easier to remove.
Given these trends, we can analyze the provided periodic table section to determine the atom with the highest ionization energy.
- Helium (He) is in the top right corner of the periodic table.
- Helium is located in period 1, group 18.
Considering the trends:
- Helium is in the same period as Hydrogen (H), and we know that ionization energy increases across a period.
- Helium is also at the very top of its group. As we move down the group, ionization energy decreases.
Therefore, among all the elements listed, Helium (He) will have the highest ionization energy because it is located at the top right corner of the periodic table.
Thus, the atom with the highest ionization energy is:
[tex]\[ \text{He} \][/tex]
So the correct answer is Helium (He).
