How many atoms of hydrogen are indicated in the formula

Both 5 and 6

Working with si (metric) units for each of the following commonly used measurements, indicate its symbol. liter gram milliliter kilogram meter centigram milligram centimeter kilometer second millimeter milliseconds

The mass of a neutron is equal to the mass of a proton plus the mass of an electron. true or false false true

How are isotopes of the same chemical element alike? how are they different?