Structure of atoms

• Neutrons = Mass Number + Atomic Number
• Neutrons = Mass Number - Atomic Number
• Neutrons = Atomic Number + Electrons
• Neutrons = Atomic Number - Electrons

• Mass Number = Atomic Number + Neutrons
• Mass Number = Atomic Number - Neutrons
• Mass Number = Atomic Number + Electrons
• Mass Number = Atomic Number - Electrons 

• Electrons that are inside the nucleus
• Electrons on the outermost energy level 
• Electrons that are closest to the nucleus
• Electrons that have a positive charge

• Number of protons
• Number of neutrons
• Number of electrons
• Mass Number

• Protons and Neutrons
• Protons and Electrons
• Neutrons and Electrons
• Neutrons and Valence Electrons

• The number of protons
• The number of neutrons
• The Mass Number
• The number of valence electrons

• Protons
• Neutrons
• Electrons

• It contains protons
• It contains neutrons
• It contains electrons

• Protons
• Neutrons
• Electrons

• Protons and Neutrons
• Protons and Electrons
• Neutrons and Electrons