Review- Elements, compounds, chemical formulas

Use the periodic table to identify which statement best describes carbon dioxide, CO₂.

• It is an element that consists of 3 total atoms.

• It is a molecule that consists of 3 total atoms.

• It is an element that consists of 3 total molecules.

• It is a compound that consists of 3 total molecules.

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NGSS.MS-PS1-1

Glucose has the chemical formula C₆H₁₂O₆. Which of the following is true about one molecule of glucose?

• It consists of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.

• It consists of 12 carbon atoms, 6 hydrogen atoms, and 12 oxygen atoms.

• It consists of 6 carbon atoms, 6 hydrogen atoms, and 12 oxygen atoms.

• It consists of 12 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.

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NGSS.MS-PS1-1

Elements and compounds are similar in some ways and different in others. Which statement is true?

• The chemical formula for chlorine gas is C.

• An element’s symbol must start with 2 capital letters.

• Elements are represented by a single chemical symbol.

• A compound, such as water, can have different chemical formulas.

Using the periodic table, which elements are present in the formula CaCO₃?

• carbon and cobalt

• calcium and cobalt

• calcium, carbon, and oxygen

• carbon, actinium, and oxygen

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NGSS.MS-PS1-1

Which substance is a gas at room temperature and has no flammability?

• Methane (CH4)

• Nitrogen (N2)

• 2-Methylbutane (C5H12)

• Oxygen (O2)

Compare and contrast the formulas of these two compounds: Nitrous acid (HNO₂) and Nitric acid (HNO₃). Describe the similarities and differences between the compounds. Circle TWO correct answers.

• Both compounds contain the same kinds of atoms.

• Both compounds contain the same total number of atoms.

• Nitrous acid contains fewer oxygen atoms than nitric acid.

• Nitrous acid contains more nitrogen atoms than nitric acid.

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NGSS.MS-PS1-1

Which of these are characteristics of copper?

• Copper piping is an example of a nonmetal.

• Copper piping is brittle and can break easily.

• Copper piping has the ability to conduct heat and electricity.

• Copper piping is an example of a metalloid.

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NGSS.MS-PS3-3

A student makes observations about an unknown substance. They notice that the substance is dull and brittle and a solid at room temperature. Which of these substances might fit this profile?

• aluminum

• carbon

• hydrogen

• magnesium

This is an image of the periodic table without the symbols of the elements. Which region shows the location of most rare-earth metals?

• A.

• B.

• C.

• D.

Which of the following contains only compounds?

• A. H₂O, H₂O₂, H₃O, CO₂

• B. Na₂, NaCl, Pb, C₆H₁₂O₆

• C. NH₃, KNO₃, Hg, Ne

• D. Au, Ni₂, Cu, Fe₂

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NGSS.MS-PS1-1