In the periodic table the trend of density of elements down the group generally

Options

A. increases
B. decreases
C. remains constant
D. first increases then decreases

Answer

To solve the question regarding the trend of density of elements down the group in the periodic table, we can follow these steps:

### Step 1: Understand the Definition of Density
Density is defined as mass per unit volume. It can be mathematically expressed as:
\[ \text{Density} = \frac{\text{Mass}}{\text{Volume}} \]

### Step 2: Analyze the Changes in Mass and Volume Down the Group
As we move down a group in the periodic table:
- The number of protons and neutrons (which contribute to mass) increases significantly.
- The atomic size (or volume) also increases because additional electron shells are added.

### Step 3: Compare the Rate of Change of Mass and Volume
While both mass and volume increase down the group:
- The increase in mass (due to more protons and neutrons) is generally greater than the increase in volume (due to the addition of electron shells).
- This means that the overall density will be influenced more by the increase in mass than by the increase in volume.

### Step 4: Conclude the Trend of Density
Since the increase in mass dominates over the increase in volume, the density of elements generally increases as we move down a group in the periodic table.

### Final Answer
Therefore, the trend of density of elements down the group generally **increases**.

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