Moving from right to left in a periodic table, the atomic size is :

Options

A. increased
B. decreased
C. remains constant
D. none of these

Answer

To solve the question regarding the atomic size when moving from right to left in the periodic table, we need to understand the trends in atomic size across periods.

### Step-by-Step Solution:

1. **Understanding Atomic Size**: Atomic size refers to the distance from the nucleus of an atom to the outermost shell of electrons.

2. **Periodic Table Structure**: The periodic table is arranged in periods (rows) and groups (columns). Each period corresponds to the filling of a new electron shell.

3. **Trend from Left to Right**: As we move from left to right across a period, the number of protons in the nucleus increases. This increase in positive charge attracts the electrons more strongly, pulling them closer to the nucleus.

4. **Effect on Atomic Size**: Because the electrons are pulled closer to the nucleus due to the increased positive charge, the atomic size decreases as you move from left to right across a period.

5. **Trend from Right to Left**: Conversely, when moving from right to left in a period, we are decreasing the number of protons in the nucleus. This results in a weaker attraction between the nucleus and the electrons.

6. **Conclusion**: As a result, the atomic size increases when moving from right to left across a period in the periodic table.

### Final Answer:
The atomic size increases when moving from right to left in a periodic table.