When electrons revolve in stationary orbits,

Options

A. there is no change in energy level
B. they become stationary
C. they are gaining kinetic energy
D. there is increase in energy

Explanation

To solve the question "When electrons revolve in stationary orbits," we need to understand the concept of stationary orbits in the context of atomic structure. Here’s a step-by-step solution:

### Step 1: Understand the Concept of Stationary Orbits
In atomic theory, stationary orbits refer to the specific paths that electrons can occupy around the nucleus of an atom without radiating energy. These orbits are defined by quantum numbers.

**Hint:** Remember that stationary orbits are stable and do not emit energy.

### Step 2: Identify the Principal Quantum Number
Each stationary orbit corresponds to a principal quantum number (n). For example, n=1 is the first orbit, n=2 is the second orbit, and so on. The energy of the electron in these orbits is quantized and depends on the value of n.

**Hint:** The principal quantum number indicates the energy level of the electron.

### Step 3: Recognize Energy Levels
When an electron is in a stationary orbit, it has a fixed energy level associated with that orbit. For instance, an electron in the first orbit (n=1) has a specific energy (E1), while an electron in the second orbit (n=2) has a different fixed energy (E2).

**Hint:** Energy levels are quantized and do not change unless the electron moves to a different orbit.

### Step 4: Understand Absorption and Emission
Electrons can only change their energy levels by absorbing or emitting energy (photons). If an electron is in a stationary orbit and not absorbing or emitting energy, its energy remains constant.

**Hint:** Energy changes occur only when electrons transition between orbits.

### Step 5: Conclusion
Since the question states that the electrons are revolving in stationary orbits, it implies that there is no change in energy levels. Therefore, the correct answer is that there is no change in energy level when electrons are in stationary orbits.

**Final Answer:** There is no change in energy level.