Atomic Unit

What was the first subatomic particle to be discovered?

• Proton

• Neutron

• Electron

• Positron

Rutherford, during his Gold Foil Experiment, observed that most of the alpha particles passed straight through the gold foil. What conclusion can be drawn

• The atom is indivisible

• The atom is mostly empty space

• The atom has a nucleus

• Electrons are outside the nucleus

An orbital is a region in an atom where there is a high probability of finding

• an Alpha particle

• an electron

• a neutron

• a positron

Who proposed the atomic theory that stated atoms of the same element are identical?

• John Dalton

• Ernest Rutherford

• J.J. Thomson

• Neils Bohr

Which model of the atom proposed that electrons move in fixed orbits around the nucleus?

• Thomson's Model

• Rutherford's Model

• Bohr's Model

• Dalton's Model

What is the charge of a neutron?

• Positive

• Negative

• Neutral

• Variable

How many neutrons are in ¹⁹₉F?

• 19

• 9

• 10

• 28

How many protons are in a lithium atom?

• 3

• 4

• 7

• 10

Who discovered the neutron?

• James Chadwick

• Ernest Rutherford

• J.J. Thomson

• John Dalton

What is the atomic number of an element?

• Number of protons in the nucleus

• Number of neutrons in the nucleus

• Number of electrons in the atom

• Number of protons and neutrons in the nucleus