Question

1. neutral atoms of cl are bombarded by high energy (light energy), causing the ejection of electrons from various filled subshells. electrons from which subshell would have the highest velocity after being ejected? justify your answer.

Explanation:

To solve this, we analyze the electron configuration of neutral chlorine (Cl) atoms and the concept of ionization energy (related to electron removal and velocity after ejection, as higher energy electrons (less tightly bound) will have higher velocity when ejected).

Step 1: Determine the electron configuration of Cl

The atomic number of Cl is 17. Its electron configuration is:
$$1s^2 2s^2 2p^6 3s^2 3p^5$$

Step 2: Analyze subshell energy levels

Electron energy levels follow the order of filling: \(1s < 2s < 2p < 3s < 3p < \dots\) (approximate, based on Aufbau principle). However, ionization energy (energy required to remove an electron) is inversely related to how "loosely" an electron is held. Electrons in outer (higher - n) subshells are held less tightly (lower ionization energy) than inner - shell electrons.

For Cl:

• Inner shells: \(1s, 2s, 2p\) (electrons here are very tightly bound, high ionization energy to remove).
• Outer shells: \(3s, 3p\) (electrons here are less tightly bound).

Among \(3s\) and \(3p\): The \(3p\) subshell has a higher energy than the \(3s\) subshell (since \(3p\) electrons experience more shielding and have a higher principal quantum number - related energy, and in Cl, the \(3p\) subshell is only 1 electron away from a stable octet, but for ejection (photoelectric - like effect, where light energy ejects electrons), the key is the binding energy of the electron). Wait, actually, the binding energy (energy required to remove the electron from the atom) is lower for electrons in higher - energy subshells. So electrons with lower binding energy will gain more kinetic energy (and thus higher velocity) when ejected by a photon of fixed energy (since \(KE = h
u - BE\), where \(h
u\) is photon energy, \(BE\) is binding energy).

Step 3: Identify the subshell with the least - bound (highest - energy) electrons

In Cl’s electron configuration, the outermost subshell is \(3p\) (with 5 electrons, and the \(3s\) has 2). The \(3p\) electrons are in a higher - energy subshell than \(3s\) (due to shielding and angular momentum quantum number effects: \(l = 0\) for \(s\), \(l = 1\) for \(p\); for the same \(n = 3\), \(E_{3p}>E_{3s}\)). Electrons in \(3p\) have lower binding energy (since they are farther from the nucleus, on average, and experience more shielding) than \(3s\) electrons, and much lower than \(2p, 2s, 1s\) electrons.

Step 4: Relate binding energy to velocity after ejection

When a photon ejects an electron, the kinetic energy of the ejected electron is \(KE=\text{Photon Energy}-\text{Binding Energy of Electron}\) (assuming photon energy is greater than binding energy). For a given photon energy (high - energy photons, so we can assume \(h
u\) is large enough to eject electrons from multiple subshells), electrons with lower binding energy (higher - energy subshells) will have higher kinetic energy. Since \(KE = \frac{1}{2}mv^2\) (mass \(m\) of electron is constant), higher \(KE\) means higher velocity \(v\).

So, electrons from the \(3p\) subshell of Cl will have the highest velocity after being ejected, because they have the lowest binding energy (highest subshell energy among occupied subshells) in the Cl atom, leading to the highest kinetic energy (and thus highest velocity) when ejected by a high - energy photon.

Answer:

Electrons from the \(3p\) subshell of neutral Cl atoms will have the highest velocity after ejection. This is because the \(3p\) subshell electrons have the lowest binding energy (highest energy among occupied subshells in Cl’s electron configuration: \(1s^2 2s^2 2p^6 3s^2 3p^5\)). Using the kinetic energy formula for ejected electrons (\(KE=\text{Photon Energy}-\text{Binding Energy}\)) and \(KE = \frac{1}{2}mv^2\), lower binding energy (for \(3p\) electrons) gives higher kinetic energy and thus higher velocity (since electron mass \(m\) is constant).