protons and neutrons.
both are present in the nucleus.
The electron is the subatomic particle with the least mass. It has a mass of about 1/1836 of a proton or neutron.
A neutron is the subatomic particle with a charge of 0 and a mass of 1 atomic mass unit.
An "element" is not a subatomic particle. Your question makes no sense and is therefore unanswerable.Another answer:Since an element is not a subatomic particle, the only answer can be a proton.
The tau neutrino has mass and is denoted with the symbol μ.
The neutron is a subatomic particle that has mass nearly equal to that of a proton but carries no electrical charge.
No such particle exists. All particles with charge also have mass -- no exceptions. Every particle with zero mass also has zero charge -- no exceptions.
Matter
Protons and neutrons have the mass of 1 amu.
The electron has the smallest mass between subatomic particles: 9,10938291(40).10-31 kg.
Both one proton and one neutron each has a relative mass of 1 a.m.u.
Technically all subatomic particles have mass. However, the electron is so small that it was once considered to have no mass. Wrong, both photons and gravitons are subatomic particles with no mass.
the neutron