During diffusion substances move from the denser medium (meaning where there is more of the substance) to less dense medium (meaning where there is less of the substance).
6.9 x 10^-4 would be .00069 written in scientific notation
Its phosphorus (P)In writing the electron configuration for Phosphorus the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Phosphorous go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the remaining three electrons. Therefore the Phosphorus electron configuration will be 1s22s22p63s23p3.
When temperature of liquid is increased, liquid gets thinner and thinner and hence it's viscosity decreases.
Density = mass/volume.
As we increase the temperature, volume of the liquid starts to increase but mass of the liquid remains constant. As a result, density of liquid decreases.
Hope this helps!