#1 The nucleons are
A nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus.
#2 The isotope deuterium of hydrogen has
Deuterium is a hydrogen isotope consisting of one proton, one neutron and one electron. It has major applications in nuclear magnetic resonance studies.
#3 The electrons present in the outermost shell are called
The electrons in the outermost occupied shell (or shells) determine the chemical properties of the atom; it is called the valence shell. Each shell consists of one or more subshells, and each subshell consists of one or more atomic orbitals.
#4 An alpha particle contains
The alpha particle is a helium nucleus; it consists of two protons and two neutrons. It contains no electrons to balance the two positively charged protons and mass 4 unit.
#5 The atomic number of sodium is 11 and its mass number is 23. It has
Since it has an atomic number of 11 it must have 11 protons. Since it has an atomic mass of 23 it must have 12 neutrons. If it is electrically neutral, it will have 11 electrons.