To determine whether the ice block will float or sink, we need to calculate its density and compare it to the density of water, which is about 1 g/cm³. The volume of the ice block can be calculated using the formula for volume: \( \text{Volume} = \text{height} \times \text{length} \times \text{width} \), which gives us \( 2 \text{ cm} \times 2 \text{ cm} \times 5 \text{ cm} = 20 \text{ cm}^3 \).
Next, we can find the density of the ice block by dividing its mass by its volume: \( \text{Density} = \frac{\text{mass}}{\text{volume}} = \frac{18.4 \text{ g}}{20 \text{ cm}^3} = 0.92 \text{ g/cm}^3 \). Since the density of the ice block (0.92 g/cm³) is less than the density of water (1 g/cm³), the block will float. Thus, the ice block will not sink when it is dropped into water.