The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided?

• element

• atom

• electron

• molecule

Rutherford's gold foil experiment provided evidence for which of the following statements?

• Negative and positive charges are spread evenly throughout an atom.

• Alpha particles have a positive charge.

• Gold is not as dense as previously thought.

• There is a dense, positively charged mass in the center of an atom.

Tags

NGSS.HS-PS1-8

In an atomic model that includes a nucleus, positive charge is

• concentrated in the center of an atom

• spread evenly throughout an atom.

• concentrated at multiple sites in an atom

• located in the space outside the nucleus

Tags

NGSS.HS-PS1-8

Which subatomic particle has a negative charge?

• electron

• alpha particle

• proton

• neutron

Which statement about subatomic particles is true?

• Protons, neutrons, and electrons all have about the same mass.

• Unlike protons or neutrons, electrons have no mass.

• Neutrons have no charge and no mass.

• An electron has far less mass than either a proton or neutron.

Which of the following is unique for any given element?

• the number of neutrons

• the charge on the electrons

• the number of protons

• the mass of a neutron

The number of protons in one atom of an element is that element's

• mass number.

• balanced charge.

• atomic number.

• isotope.

How would you find the number of neutrons in a an atom?

• atomic number - mass number

• mass number - atomic number

• electron number - atomic number

• atomic number - isotope number

Tags

NGSS.MS-PS1-1

Which statement is true about oxygen-17 and oxygen-18?

• They do not have the same number of protons.

• Their atoms have an identical mass.

• They are isotopes of oxygen.

• They have the same mass number.

Tags

NGSS.MS-PS1-1

In Niels Bohr's model of the atom, electrons move

• like balls rolling down a hill.

• like planets orbiting the sun.

• like popcorn in a popcorn popper.

• like beach balls on water waves.

Tags

NGSS.HS-ESS1-4