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?

b. atoms in metallic solids are not arranged in a regular pattern

explanation:

i believe it is 40–40–20%

explanation:

that's what i got you can count the number of atoms

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.