Atomic Structure, Atomic Number, Mass Number

What are the three sub-atomic particles found in an atom?

Which sub-atomic particles are found in the nucleus of an atom?

• protons only

• neutrons and electrons

• protons and electrons

• protons and neutrons

Which sub-atomic particles contribute the most to the mass of an atom?

• protons only

• electrons only

• protons and electrons

• protons and neutrons

What is the charge of an electron?

• +1

• -1

• 0

An atom has an equal number of positively charged protons and negatively charged electrons, thus it is said to be (a)   .

What is atomic number?

• number of neutrons

• number of neutrons and protons

• number of protons

• number of electrons

What is the atomic number of this atom?

• 4

• 5

• 8

• 9

What is mass number?

• number of protons

• number of electrons

• number of protons and electrons

• number of protons and neutrons

What is the mass number of Potassium?

• 19

• 20

• 39

• 58

How many neutrons does an atom of Potassium have?

• 19

• 20

• 39

• 58