SC 8 P 8 4

Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr) are in the same column in the periodic table. Why are these elements in the same column in the periodic table?

• They are the same size

• They react with each other

• They have similar properties

• They have the same number of protons

Any atom that has 19 protons is a potassium (K) atom. Which statement best describes what would happen if a proton was added to potassium atom?

• The atom will lose electrons

• The atom would have a negative charge.

• The atom would no longer be potassium

• The atom would have a smaller atomic number.

Tags

NGSS.MS-PS1-1

What do elements in the same group on the periodic table have in common?

• They have similar chemical symbols

• They have the same atomic number.

• They have similar chemical properties

• They have the same average atomic mass

Which of the following statements best describes pure substances?

• Pure substances consist of substances that have been combined together through physical processes

• Pure substances consist of substances that have been separated through physical processes

• Pure substances are substances that are always made of one type of atoms

• Pure substances consist of substances that have definite physical and chemical properties

Krystal is exploring the properties of iron. She takes a large iron nail and finds that the nail does not attract other metal objects. Next, she uses a battery and copper wire to transform the nail into an electromagnet. When she connects the circuit, the nail becomes magnetic and can pick up small metal objects like paper clips. This is shown in the illustration below.  What best describes what has happened to the iron in the nail that causes it to become magnetic?  

• A physical change has occurred, because the chemical properties of the iron remain the same

• A physical change has occurred, because there is a chemical attraction between the iron and paper    clips

• A chemical change has occurred, because there is a chemical attraction between the iron and paper   clips

• A chemical change has occurred, because the chemical energy in the battery is transformed into   magnetic energy in the iron

Tags

NGSS.MS-PS1-2

Carbon dioxide (CO 2) is a substance that is a gas at room temperature. At temperatures below 78°C,  carbon dioxide condenses into a white solid known as dry ice. At normal atmospheric pressures, dry ice changes directly from a solid to a gas without passing through a liquid phase when its temperature increases. This process is called sublimation. Which of the following best describes the process of sublimation?

• It is a chemical reaction, because the kinetic energy of the molecules is changing

• It is a physical reaction, because it is a change of state

• It is a physical reaction, because the density of the material increases

• It is a chemical reaction, because a new form of carbon dioxide is created.

Tags

NGSS.MS-PS1-4

Why is the formation of rust considered a chemical change?

• Rust is more reactive than oxygen

• Rust has the same chemical composition as iron

• Rust has a lower density than iron

• Rust has properties that are different from iron and oxygen

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Amanda investigated physical and chemical changes in science class and then classified her changes into two columns shown. Column A are the chemical changes and Column B are the physical changes. Which statement below best explains why the processes in Column B are physical changes?

• The change has formed new substances

• The shape of the substance has changed

• The change that occurred can be reversed easily

• The characteristics of the original substance have not changed

Tags

NGSS.MS-PS1-2

Amanda investigated physical and chemical changes in science class and then classified her changes into two columns shown. Column A are the chemical changes and Column B are the physical changes. Which statement below best explains why the processes in Column A are chemical changes?

• The change has formed new substances

• The shape of the substance has changed

• The change that occurred can be reversed easily

• The characteristics of the original substance have not changed

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Ethan is observing chemical and physical properties of a substance. He heats a substance and observes that the substance turns from a brown solid to a black powder. He refers to several chemistry journals that claim this represents a chemical reaction. From his observation and research, he concludes that the substance goes through a chemical change when heated. How can Ethan best defend his conclusion?

• By verifying that the substance is made up of only one type of element

• By demonstrating that the substance has the same density after it is heated

• By verifying that the substance is now made up of different molecules than before it was heated

• By demonstrating that the substance will eventually melt if the temperature continues to increase

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4