Identify the step in which droplets of water clump together around tiny dust particles in the air.

The correct answer is condensation.  

The procedure by which the droplets of water gets transformed back to liquid water is known as condensation. The step of condensation is very essential to the climate and weather as it is majorly responsible for the formation of cloud. The formation of the cloud takes place when the water vapor condenses around small particles, like smoke or dust in the air.  

the answer for sodium is 0.186

the answer for rubidium is 0.251

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.