The mass of the helium nucleus is 6.64 x 10^-27 kilograms. The mass is calculated by adding together the mass of two protons, each of which has a mass of 1.67 x 10^-27 kilograms and two neutrons, which each have a mass o... More »

The nucleus of an atom is surrounded by an electron cloud that is held in place by an electromagnetic force. The nucleus accounts for significantly more of the atom's total mass than the cloud, although the cloud account... More »

The nucleus of an atom is the region found in the center of the atom. It consists of the protons and neutrons. The nucleus makes up the majority of an atom's mass; the other part making up the atom's mass is the outer el... More » Science Chemistry Atoms & Molecules

One atom of helium has two protons in its nucleus. A neutral atom of helium also has two electrons. More »

Helium results from the fusion of four hydrogen nuclei to form one helium nucleus. This reaction also generates energy and is the source of power at the core of stars. More » Science Chemistry Atoms & Molecules

The nucleus of helium contains two neutrons and two protons. Around the nucleus of helium there are two electrons in the 1s orbital. These have opposite spins. More »

The atomic mass of an element is determined by the number of subatomic particles in the nucleus. The subatomic particles contained within a nucleus are called protons and neutrons. More » Science Chemistry Atoms & Molecules