Chemistry Review

Which of the subatomic particles has the smallest mass?

• They all have the same mass.
• Neutrons
• Protons
• Electrons

An unidentified element has many of the same physical and chemical properties as magnesium and strontium but has lower atomic mass than either of these elements. What is the most likely identity of this element?

• Beryllium
• Sodium
• Calcium
• Barium

An unidentified element has many of the same physical and chemical properties as sodium and rubidium but has lower atomic mass than either of these elements. What is the most likely identity of this element?

• potassium
• beryllium
• lithium
• cesium

The net charge on an aluminum ion is +3 because there are

• 13 protons and 10 electrons
• 10 protons and 13 electrons
• 13 protons and 10 neutrons
• 10 neutrons and 13 electrons

The net charge on an oxygen ion is -2 because there are

• 8 protons and 10 neutrons
• 8 protons and 10 electrons
• 10 protons and 8 electrons
• 10 protons and 8 neutrons

Select the correct electron configuration for Cl.

• 1s² 2s² 2p⁶ 3s² 3p⁵
• 1s² 2s² 3s² 3p⁶ 4s² 4p³
• 1s² 2s² 2p⁶ 4s² 4p⁵
• 1s² 2s² 2p⁶ 3s¹ 3p⁶

Which of the following BEST describes why atoms form bonds?

• Atoms bond to change from liquid to gas.
• Atoms bonds to make new substances.
• Atoms bond to change from liquid to solid.
• Atoms bond to be more chemically stable.

Do the following isotopes belong to the same element? Explain.
Aluminum-27
An isotope with 14 protons and 13 neutrons

• No because they have different number of neutrons.
• Yes because they have the same number of protons.
• Yes because they have the same mass number.
• No because they have different number of protons.

Which of the following pairs of elements will form an ionic bond?

• O and Cl
• Ni and N
• Sn and Cu
• H and C

What element has the valence shell configuration 4s² 4p²?

• Se
• Ti
• Ca
• Ge