Atom R has a total of 58 elementary particles, in which the ratio of the number of neutrons to the mass number is 20/39. Give the number of particles of each type in R and the atomic symbol R?

What is the formula that this ionic compounds could form sr2+p3-o2-

If 15 drops of ethanol from a medical dropper weight 0.60g, how many drops does it takes from a dropper to dispense 1.0ml of ethanol? the density of ethanol is 0.80g/ml

The following transition occurs at a molecular level for a substance. what transition corresponds to this change in microscopic structure? the carbon dioxide molecules on the left are in a regular, tightly packed pattern. after heating, it becomes much lower density. a. melting b. boiling c. sublimation d. freezing