Which element has 31 protons in its nucleus?

In an atom or ion, which subatomic particle(s) determine the net electric charge?

Which statement correctly describes a property of a neutron in an atom?

In a neutral atom, which subatomic particle carries a negative charge?

Which neutral atom has 6 electrons?

In a simplified model of the atom, which subatomic particles are considered the heavy particles (i.e., account for nearly all of the atom’s mass)?

In early atomic theory, which scientist is commonly credited with calculating the electron’s charge-to-mass ratio and thereby enabling determination of the electron’s mass?

How many protons are in a neutral atom of copper (Cu)?

How many protons are there in a neutral chlorine atom ($Cl$)?