What is the smallest unit of matter that retains the properties of an element?
Atom
True or False: Electrons have a positive charge.
False
Fill in the blank: The nucleus of an atom contains protons and __________.
neutrons
Which subatomic particle is found in the nucleus and has a positive charge?
Proton
What is the mass number of an atom equal to?
The sum of protons and neutrons in the nucleus