Question

It always takes energy to remove an electron from an atom, no matter what \(n\) shell the electron is in. Also, the higher the \(n\), the more energy an electron starts out with. (a) Explain why it takes energy to remove an electron from an atom no matter what \(n\) shell it is in. (b) Why does it take less energy to remove an electron from an atom the higher its \(n\) value?

Short answer

(a) It takes energy to remove an electron from an atom no matter what \(n\) shell it is in because there is always some degree of attraction between the negatively charged electron and the positively charged nucleus. To remove an electron, energy must be applied to overcome this electrostatic attraction. (b) It takes less energy to remove an electron from an atom the higher its \(n\) value because electrons in higher shells are further from the nucleus, experiencing less attraction to it. Since electrons in higher \(n\) shells have weaker attraction to the nucleus, less energy is required to overcome this attractive force and remove them from the atom.

Step-by-step solution

Understanding electron removal from an atom

To begin, it is important to understand that electrons reside in specific energy levels, or shells, around the nucleus of an atom. These shells are represented by the quantum number \(n\). Electrons in lower shells (lower \(n\) values) are closer to the positively charged nucleus, meaning they are more attracted to it, while electrons in higher shells (higher \(n\) values) are further from the nucleus and experience less attraction. To remove an electron from an atom, we have to overcome the attractive force between the negatively charged electron and the positively charged nucleus.

(a) Explaining energy requirements for electron removal

No matter which shell the electron is in, there is always some degree of attraction between the negatively charged electron and the positively charged nucleus. This means that we always need to apply energy in order to break this electrostatic attraction and remove the electron from the atom. In essence, we need to provide enough energy for the electron to overcome the attractive force exerted by the nucleus, thereby allowing it to escape the atom. Thus, it takes energy to remove an electron from an atom no matter what \(n\) shell it is in.

(b) Understanding the relationship between energy requirements and \(n\) value

The higher the \(n\) value, the further away the electron is from the positively charged nucleus. This means the electrostatic force of attraction between the nucleus and the electron decreases as \(n\) increases. Consequently, electrons in higher shells have less energy holding them to the nucleus than those in lower shells. When it comes to removing an electron from an atom, we need to provide enough energy for the electron to overcome the attractive force exerted by the nucleus. Since electrons in shells with higher \(n\) values have weaker attraction to the nucleus, it takes less energy to remove them from the atom compared to electrons in shells with lower \(n\) values. This is why it takes less energy to remove an electron from an atom the higher its \(n\) value.

Key concepts

Quantum Number

The quantum number, often symbolized by \( n \), is a crucial concept in understanding the behavior of electrons in an atom. It describes the principal energy level or shell where an electron is located. Quantum numbers start from \( n = 1 \) and increase as electrons reside in shells further away from the nucleus.

As the quantum number increases, the average distance of the electron from the nucleus also increases. This means that electrons with higher quantum numbers are positioned farther from the positively charged nucleus.

Understanding this helps us explain why electrons in higher shells have higher energy levels. The further an electron is from the nucleus, the less tightly it is held by the attractive force of the positively charged protons. This makes it easier, or requires less energy, to remove an electron from higher shells.

Energy Levels

Energy levels refer to the specific energies that electrons can have when they occupy certain shells, which are labeled by the quantum number \( n \). Each energy level corresponds to a particular shell surrounding the nucleus of an atom.

The closer the shell is to the nucleus, the lower its energy level. Therefore, electrons in inner shells (lower \( n \) values) are at lower energy levels compared to those in outer shells.

• Energy increases as we move to higher shells (higher \( n \) values).
• Electrons in lower energy levels are held more tightly by the nucleus.
• Moving an electron to a higher energy level requires an input of energy.

Electrons in higher shells require less energy to be removed because they start with more energy and are not held as tightly by the nucleus.

Electrostatic Attraction

Electrostatic attraction is the force that pulls oppositely charged particles towards each other. In the case of an atom, it is the attraction between the negative electrons and the positive protons in the nucleus.

This force is fundamental in explaining why energy is needed to remove an electron from an atom. The closer an electron is to the nucleus, the stronger the electrostatic attraction it experiences. This means:

• Electrons in lower \( n \) shells are held more strongly by the nucleus.
• Thus, removing one of these electrons requires more energy to overcome the attraction.
• In contrast, electrons in higher \( n \) shells experience weaker attraction, needing less energy for removal.

Understanding electrostatic attraction helps us see why the energy needed to remove an electron varies depending on its distance from the nucleus.