Question

the mass number tells you the number of______in an atom *
protons + neutrons
neutrons
electrons
protons
the atomic number tells you the number of______in an atom *
protons + neutrons
neutrons
protons and electrons
electrons
how do you find the number of neutrons in the nucleus of an atom? *
mass number - atomic mass
atomic number - electrons
protons + electrons
mass number - atomic number

Explanation:

• For the first question, the mass number is defined as the sum of protons and neutrons in an atom.
• For the second question, the atomic number is equal to the number of protons (and in a neutral atom, also equal to the number of electrons).
• For the third question, the formula to find the number of neutrons is mass number - atomic number.

Answer:

• First question: Protons + Neutrons
• Second question: Electrons (in a neutral atom, atomic number = number of protons = number of electrons)
• Third question: mass number - atomic number