(a) What is the general relationship between the size of an atom and its first ionization energy?

Verified step by step guidance

1. Understand that the first ionization energy is the energy required to remove the outermost electron from a neutral atom in the gaseous state.
2. Recognize that atomic size refers to the distance from the nucleus to the outermost electron shell of an atom.
3. Recall that as atomic size increases, the outermost electrons are further from the nucleus and experience less electrostatic attraction, making them easier to remove.
4. Note that as atomic size decreases, the outermost electrons are closer to the nucleus and experience a stronger electrostatic attraction, making them harder to remove.
5. Conclude that there is an inverse relationship between atomic size and first ionization energy: as atomic size increases, first ionization energy decreases, and vice versa.

Key Concepts

Atomic Size

Atomic size refers to the distance from the nucleus to the outermost electron shell of an atom. As you move down a group in the periodic table, atomic size increases due to the addition of electron shells, which increases the distance between the nucleus and the outer electrons. Conversely, atomic size decreases across a period from left to right due to increased nuclear charge, which pulls the electrons closer to the nucleus.

Ionization Energy

Ionization energy is the energy required to remove an electron from an atom in its gaseous state. It is influenced by the atomic size and the effective nuclear charge experienced by the outermost electrons. Generally, as atomic size increases, ionization energy decreases because the outer electrons are further from the nucleus and experience less electrostatic attraction, making them easier to remove.

Trends in the Periodic Table

The periodic table exhibits specific trends in atomic size and ionization energy. As you move down a group, atomic size increases and ionization energy decreases. In contrast, moving from left to right across a period, atomic size decreases while ionization energy increases. Understanding these trends helps predict how changes in atomic structure affect the energy required to ionize an atom.