Question

Which of these electron transitions correspond to absorption of energy and which to emission? (a) \(n=2\) to \(n=4\) (b) \(n=3\) to \(n=1\) (c) \(n=5\) to \(n=2\) (d) \(n=3\) to \(n=4\)

Short answer

(a) Absorption (b) Emission (c) Emission (d) Absorption

Step-by-step solution

Understanding Electron Transitions

An electron transition involves an electron moving from one energy level (orbital) to another within an atom. When an electron moves to a higher energy level, it absorbs energy. Conversely, when it moves to a lower energy level, it emits energy.

Analyze Transition (a) from n=2 to n=4

The electron moves from a lower energy level (n=2) to a higher energy level (n=4). This means the electron is absorbing energy.

Analyze Transition (b) from n=3 to n=1

The electron moves from a higher energy level (n=3) to a lower energy level (n=1). This means the electron is emitting energy.

Analyze Transition (c) from n=5 to n=2

The electron moves from a higher energy level (n=5) to a lower energy level (n=2). This means the electron is emitting energy.

Analyze Transition (d) from n=3 to n=4

The electron moves from a lower energy level (n=3) to a higher energy level (n=4). This means the electron is absorbing energy.

Key concepts

Energy Absorption

Energy absorption occurs when an electron moves from a lower energy level to a higher energy level. In simpler terms, the electron needs to gain extra energy to jump to a further orbital from the nucleus. Think of it like climbing a ladder; each step up requires more energy.

For example:
When the electron transitions from \( n=2 \) to \( n=4 \) (like in step (a) of the problem), it must absorb energy to make this jump.

Another case of energy absorption is in the transition from \( n=3 \) to \( n=4 \) as found in step (d) of the problem. So, anytime you are moving to a higher-energy state, it's likely energy absorption.

Energy Emission

Energy emission is the opposite process of energy absorption. When an electron falls from a higher energy level to a lower energy level, it emits energy in the form of light or other electromagnetic radiation.

To put it simply, it's like sliding down a slide; energy is released during the descent.

For example:
When the electron transitions from \( n=3 \) to \( n=1 \) (like in step (b) of the problem), it releases energy.

Another example is the transition from \( n=5 \) to \( n=2 \) as found in step (c). Here, energy is emitted as the electron drops to a lower energy state. So, anytime you are moving to a lower-energy state, it's likely energy emission.

Energy Levels

Energy levels refer to the specific energies that an electron in an atom can have. These are usually denoted by the principal quantum number \( n \). Each energy level corresponds to a different orbit around the nucleus, where an electron is most likely to be found.

The principal quantum number increases as you move further from the nucleus, meaning the energy levels get higher. For example, \( n=1 \) is the lowest energy level (closest to the nucleus), while \( n=2 \) is higher, and so forth.

So, moving from \( n=2 \) to \( n=4 \) means moving to a higher energy level, while moving from \( n=5 \) to \( n=2 \) means dropping to a lower energy level.

Electron Orbitals

Electron orbitals are regions around an atom's nucleus where electrons are likely to be found. Each orbital can hold a certain number of electrons and is associated with particular energy levels.

The type of orbital (s, p, d, or f) also determines the shape and energy of the region. For instance:

• s-orbitals are spherical
• p-orbitals are dumbbell-shaped
• d and f orbitals have more complex shapes.

Electrons fill up lower-energy orbitals first (closer to the nucleus) and then move to higher-energy orbitals as they gain energy. Transitions between these orbitals involve either absorbing or emitting energy, thus linking closely with the concepts of energy absorption and emission.