7th Grade 7.PS1 Assessment Questions

Based on the diagram and the periodic table, which three statements correctly describe a silicon atom?

• Electrons are not present in the nucleus of a silicon atom.

• There are 14 protons in the nucleus of a silicon atom.

• Silicon atoms have no electrons.

• A silicon atom should have 16 protons.

• There are equal numbers of protons and neutrons in a silicon atom with a mass number of 28.

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NGSS.MS-PS1-1

The student describes particles on the edge of the atom. Which statement supports the student’s claim that the particles on the edge of the atom do not move away from the center?

• The particles are connected to the center by an object similar to a rope.

• The particles are attracted to the center because they have a charge opposite to the center’s charge.

• The particles are held in place because atoms are a solid structure.

• The particles are pushed toward the center by the nuclear charges of other atoms.

A student develops a model of a helium atom using chalk and circles. Which two labels should the student add to describe parts of the model?

• The gray circles are neutrons that have a negative charge.

• The dashed black ring is an orbital and has an overall negative charge.

• The solid black ring is the nucleus, which has an overall neutral charge.

• The white circles are protons and have a positive charge.

• The black circles are electrons and have a neutral charge.

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NGSS.MS-PS1-1

Which model best shows the structure of element X?

• A

• B

• C

• D

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NGSS.MS-PS1-1

What would be the number of valence electrons in the structure of element Z?

• 2

• 5

• 6

• 8

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NGSS.MS-PS1-1

Which statement correctly describes one of the substances?

• A. Ammonia gas is a substance made from atoms of the elements nitrogen and hydrogen, and each atom has a nucleus containing the same number of neutrons.

• B. Argon gas is a substance made from atoms of the element argon, and each atom has a nucleus containing the same number of protons.

• C. Carbon monoxide gas is a substance made from atoms of the elements carbon and oxygen, and each atom has a nucleus containing the same number of electrons.

• D. Ozone gas is a substance made from atoms of the element oxygen, and each atom has a nucleus containing the same number of electrons.

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NGSS.MS-PS1-1

Which statement explains the principle used behind the model made by the student?

• The atomic radius of elements increases from left to right across the periodic table.

• The atomic radius of elements decreases from left to right across the periodic table.

• The atomic radius of elements increases from top to bottom of the periodic table.

• The atomic radius of elements decreases from top to bottom of the periodic table.

An atom of the element strontium has 38 protons, 38 electrons, and 50 neutrons. What is the atomic mass of strontium?

• 38; the atomic mass is the number of protons.

• 50; the atomic mass is the number of neutrons.

• 76; the atomic mass is the number of protons and electrons.

• 88; the atomic mass is the number of protons and neutrons.

A student creates rules to make a model of an atom. Which model of an atom correctly uses the rules?

• A

• B

• C

• D

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NGSS.MS-PS1-1

A student was reading about the gases in air. Ozone helps protect Earth from harmful ultraviolet rays that come from the sun. Certain types of pollution created by humans have caused a hole in the ozone layer. This hole is over the South Pole and could become larger if this type of pollution increases. Which question should the student ask to determine if ozone is an elemental molecule?

• What is the color of the molecule?

• What is the shape of the molecule?

• What elements are present in the molecule?

• How many atoms are present in the molecule?

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NGSS.MS-PS1-1