With the increases in atomic number in period

Options

A. metallic character decreases
B. metallic character increases
C. chemical reactivity decreases
D. atomic size increases

Answer

To answer the question regarding the changes that occur with the increase in atomic number along a period, we can break down the solution into clear steps:

### Step-by-Step Solution

1. **Understanding Periodic Trends**:
- When we talk about the periodic table, a period is a horizontal row of elements. As we move from left to right across a period, the atomic number of the elements increases.

2. **Identifying Elements in a Period**:
- For example, in the second period, the elements are Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F), and Neon (Ne). Their atomic numbers are 3, 4, 5, 6, 7, 8, 9, and 10, respectively.

3. **Metallic Character**:
- As we move from left to right across a period, the metallic character of the elements decreases. This means that elements on the left (like Lithium) are more metallic than those on the right (like Neon).

4. **Reason for Decrease in Metallic Character**:
- The decrease in metallic character is due to the increase in effective nuclear charge (Z-effective). As the atomic number increases, the number of protons in the nucleus also increases, which enhances the attraction between the nucleus and the valence electrons. This makes it harder for the atom to lose electrons, which is a characteristic of metals.

5. **Atomic Size**:
- Along a period, the atomic size decreases. This is because the increased nuclear charge pulls the electrons closer to the nucleus, resulting in a smaller atomic radius.

6. **Non-Metallic Character**:
- Conversely, as metallic character decreases, non-metallic character increases. Non-metals tend to gain electrons, and their reactivity increases as you move from left to right across a period.

7. **Conclusion**:
- Therefore, the correct statements regarding the increase in atomic number along a period are:
- Metallic character decreases.
- Atomic size decreases.
- Non-metallic character increases.