מבוך כרית רגל מומחיות atomic number z and a גורד שחקים קם במקום סבך
Neutron Number | Definition & Characteristics | nuclear-power.com
1 Revision - Atoms Atomic number, Z, number of protons in the nucleus. Atomic symbol, X, one or two letter code – uniquely related to atomic number. Mass. - ppt download
Confused by notation of atomic number Z and mass number A on periodic table of elements - Chemistry Stack Exchange