The precise figure varies from element to element and isotope to isotope depending on the number of neutrons in the nucleus, however it is always at least 99.95% which is the ratio between an electron and a proton.
The mass of a hydrogen nucleus is approximately 1 atomic mass unit.
The hydrogen-1 nucleus is the same as the mass of a proton - since it is a proton. The proton's mass is 1.67×10−27 kg. Other nuclei have several times this mass - up to about 250 times the mass of a hydrogen nucleus.
Adding a neutron to an atom's nucleus increases the atom's mass without changing its charge. Neutrons contribute to the stability of the nucleus by balancing the repulsion of positively charged protons.
Protons and neutrons, which are found in an atom's nucleus, account for most of an atom's mass. Electrons, which orbit the nucleus, have much less mass compared to protons and neutrons.
Atoms are normally identified according to the element of which that atom is an example. And that, in turn, is determined by the number of protons in the atom's nucleus. So, any atom that has just one proton is a hydrogen atom. If it has two protons it is a helium atom. And so forth.
Hydrogen is a non metal element. Atomic mass of it is 1.
The mass of a hydrogen nucleus is approximately 1 atomic mass unit.
One mole of hydrogen molecules (H2) contains 2 hydrogen atoms per molecule, while one mole of hydrogen atoms contains single hydrogen atoms. Since the mass of a hydrogen atom is approximately half the mass of a hydrogen molecule, the molar mass of hydrogen molecules is higher than the molar mass of hydrogen atoms.
Almost all of an atom's mass is in the nucleus.
Since a neutron has mass, adding a neutron to an atomic nucleus increases the atom's mass.
The nucleus.
Three-quarters of the Sun's mass is hydrogen. How many hydrogen atoms are in the Sun?
That the mass of a helium nucleus is larger than the mass of the hydrogen nucleus. Also, since the star uses this process to produce energy, that the helium atom has less energy than the original hydrogen atoms - and therefore also less mass.
That the mass of a helium nucleus is larger than the mass of the hydrogen nucleus. Also, since the star uses this process to produce energy, that the helium atom has less energy than the original hydrogen atoms - and therefore also less mass.
the nucleus
Inside the nucleus.
Hydrogen is the lightest of all elements, having atoms that are only a fraction of the mass of all other elements. For example, an oxygen atom has about 16 times the mass of a hydrogen atom. So while a water molecule contains 2 hydrogen atoms and 1 oxygen atom (and water makes up most of the human body), the single oxygen atom accounts for most of the mass of the molecule.