Lesson 3 Electrons and Chemical Bonding textbook

A student is using colored spheres to represent atoms in a model. In which situation would this type of model be most useful?

• representing atoms in a substance in the human body

• representing the charged particles that make up individual atoms

• representing the individual energy levels in which electrons are found

• representing the relationship between electrons and the atomic nucleus

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NGSS.MS-PS1-1

Which of the following occurs when substances undergo chemical changes?

• Old atoms are destroyed and new atoms are formed.

• Atoms change from one element into another element.

• Atoms change in size and shape to form new substances.

• Bonds between atoms are broken and new bonds are formed.

You have been asked to draw a Bohr model of the element carbon. How would you arrange the dots that represent electrons?

• They would be embedded in a solid core.

• They would be in rings around the nucleus.

• They would be located in a central nucleus.

• They would be spread evenly in the shape of a cloud

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NGSS.MS-PS1-1

Sodium (Na) is in Group 1 of the periodic table. Sodium atoms readily form bonds with other atoms. Which statement best explains this property?

• Sodium boils at a higher temperature than water.

• Sodium atoms have an unequal number of protons and neutrons.

• Sodium atoms need to give up only one electron to become stable.

• Sodium atoms have a lower atomic number than most other elements have.

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NGSS.MS-PS1-5

The following image shows a section of the periodic table of the elements. Each atom of sulfur (S) has 6 valence electrons. Which of these elements also has 6 valence electrons?

• oxygen (O)

• chlorine (Cl)

• bromine (Br)

• phosphorus (P)