Atomic Theory

The mass of the electron is

• about equal to the neutron

• almost the same as the proton

• very small compared to the proton

• very large compared to the neutron

Describe the composition of the nucleus of an atom.

• it is composed of protons

• it is composed of protons and neutrons

• it is composed of protons and electrons

• it is composed of protons, neutrons,and electrons

Which statement is true for both protons and neutrons?

• They both have a neutral charge.

• They both have a positive charge.

• They are both located in the nucleus.

• They are both located outside the nucleus.

Tags

NGSS.HS-PS1-8

Describe the structure of an atom.

• The nucleus is the dense center of the atom composed of protons and neutrons. Surrounding the nucleus is an electron cloud composed of electrons.

• The nucleus is the dense center of the atom composed of electrons and neutrons. Surrounding the nucleus is an electron cloud composed of protons.

• The electron cloud is the dense center of the atom composed of electrons. Surrounding the electron cloud is a nucleus composed of protons and neutrons.

• The electron cloud is the dense center of the atom composed of protons and neutrons. Surrounding the electron cloud is a nucleus composed of electrons.

Tags

NGSS.MS-PS1-1

Three models of atomic theory are illustrated in the image. Place them in chronological order.

• A B C

• B A C

• C A B

• C B A

Tags

NGSS.MS-PS1-1

Explain how the Rutherford gold foil experiment correctly advanced atomic theory away from the "plum pudding" model.

• It proved the atom contained positive AND negative charges.

• It proved the atom contains protons, electrons, and neutrons.

• It proved that atoms are spherical in shape and not shaped like pudding.

• It proved the positive charge is concentrated in a relatively small region of the atom

In the famous gold foil experiment, radioactive particles were fired at a very thin sheet of gold foil. Most of the particles passed straight through the gold foil. Only about 1 in every 8000 particles were deflected. The gold foil experiment showed the researchers that the atom is made mostly of

• protons

• neutrons

• electrons

• empty space

Neutrons are found in the nucleus and separate the other particles so that the strong force can hold the nucleus together. Which particles are positively charged and need to be separated so that they don't repel?

• electrons

• neutrons

• protons

A _________________ is developed through the scientific method, and it can be modified or improved upon. It may be represented by a model. As seen here, three different models were used to represent atomic structure as ideas changed over time.

• hytpothesis

• law

• prediction

• theory

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-8

Scientists use various types of models to represent real world activity. For instance, computer models are used to predict weather patterns, and the physical models of Thomson and Rutherford have been used to help us understand the structure of the ____________.

• atom

• earth

• eye

• universe