Look at the two question marks between zinc (Zn) and arsenic (As). At the time, no elements were known with atomic weights between 65.2 and 75. But Mendeleev predicted that two elements must exist with atomic weights in this range. What led Mendeleev to predict that two undiscovered elements existed in that range?

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.

the answer is barium and copper bromide

your answer is c) plasma

~*"auba14"*~