When an electron is removed from an atom, its energy

Options

A. increase
B. decreases
C. remains the same
D. none of these

Explanation

To solve the question "When an electron is removed from an atom, its energy?" we can follow these steps:

### Step 1: Understand the Concept of Ionization Energy
When an electron is removed from an atom, it requires energy to overcome the attractive forces between the electron and the nucleus. This energy required to remove an electron is known as ionization energy.

**Hint:** Think about what happens when you need to pull something away from a strong attraction.

### Step 2: Identify the Type of Process
The process of removing an electron from an atom is endothermic. This means that energy is absorbed by the atom to facilitate the removal of the electron.

**Hint:** Recall the difference between endothermic and exothermic processes.

### Step 3: Analyze the Energy Change
Since energy is being supplied to remove the electron, the overall energy of the atom increases. The atom is absorbing energy to remove the outermost electron, which means its energy state is elevated.

**Hint:** Consider how energy changes when you add energy to a system versus when you take energy away.

### Step 4: Conclusion
Based on the understanding that energy is absorbed during the removal of an electron, we conclude that when an electron is removed from an atom, its energy increases.

**Hint:** Reflect on the implications of energy absorption on the state of the atom.

### Final Answer:
When an electron is removed from an atom, its energy increases.