Which element of `3rd` row has biggest atomic size?

Options

A. chlorine
B. sodium
C. silicon
D. neon

Answer

To determine which element of the third row (or period) of the periodic table has the biggest atomic size, we can follow these steps:

### Step 1: Identify the Elements in the Third Row
The elements in the third row of the periodic table are:
- Sodium (Na)
- Magnesium (Mg)
- Aluminum (Al)
- Silicon (Si)
- Phosphorus (P)
- Sulfur (S)
- Chlorine (Cl)
- Argon (Ar)

### Step 2: Understand Atomic Size Trend
Atomic size generally decreases as you move from left to right across a period in the periodic table. This is due to the increase in effective nuclear charge, which pulls the electrons closer to the nucleus, resulting in a smaller atomic radius.

### Step 3: Compare the Elements
Among the elements listed, sodium (Na) is the furthest to the left. As we move from sodium to chlorine and argon, the atomic size decreases. Therefore, sodium will have the largest atomic size in this row.

### Step 4: Conclusion
Based on the trend of atomic size across the periodic table, sodium (Na) has the biggest atomic size among the elements in the third row.

### Final Answer
The element of the third row with the biggest atomic size is **Sodium (Na)**.

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