Answer:
Chemical reaction, compound, molecule, covalent bonds, ionic bonds, ions. (first page)
Oxygen and hydrogen, 1 hydrogen 2 oxygen, H2O, a covalent bond, then mark off is always a liquid. (Second page)
Explanation:
The answer is "Figure a" i did it on plato lol
The mass percentage is 15.1465%.
There are 20n nutrons in the atom k-42.