The mass of a H- atom is less than the sum of the masses of a proton and electron. why is this?

The mass of 1 atom of hydrogen is

Identify the CORRECT statements. The mass of one mole of a substance in grams is called its molar mass. The formula mass of a substance is the sum of atomic masses of atoms present in the formula. One mole is the amount of a substance that contains as many entities or particles as there are atoms in exactly 12 g of the carbon-10 isotope.

The mass of an atom of hydrogen is 1.008u. What is the mass of 18 atoms of hydrogen.

The mass of an atom of hudrogen is 1.008u . What is the mass of 18 atoms of hydrogen ?

Answer the following questions in one sentence each : The atomic mass number of an element is 18, and the element contains 8 electrons. What is the number of protons and neutrons in it ?

The atom having the smallest atomic mass .

Calculate the mass and charge of one mole of electrons.