Unit 1: Atomic Structure Review

Identify the pair of symbols that represent isotopes of the same element.

• U-235 and U-238

• H-2 and He-2

• O-16 and O-18

Which statement best describes the properties of subatomic particles?

• Protons and neutrons contribute significant mass; electrons contribute charge.

• Neutrons and electrons contribute significant mass; protons contribute charge.

• Protons and electrons contribute significant mass; neutrons contribute charge.

• Protons and neutrons contribute charge; electrons contribute significant mass.

Which of the following has the smallest atomic mass (in grams)?

• One mole of hydrogen (H) atoms

• One mole of carbon (C) atoms

• One mole of gold (Au) atoms

• All elements have the same mass since they all contain one mole of atoms

Use the periodic table to determine which mass spectrum below most likely represents antimony (Sb).

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Which of the waves shown above represents the photon that has less energy than the other?

• Wave A has less energy.

• Wave B has less energy.

• Both waves have the same amount of energy.

• There is not enough information given to determine which wave has more energy.

Which subshell types are present in the second energy level of an atom?

• s and p

• s and d

• p and d

• d and f

Which group number does the atom in the diagram belong to?

• 2

• 4

• 16

• 18

Which of the following has the same number of valence electrons as the atom in the diagram?

• Neon (Ne)

• Phosphorus (P)

• Selenium (Se)

• Iodine (I)

How many moles of sodium are contained in 1.204 x 10^24 atoms?

• 2.00 moles Na

• 1.50 moles Na

• 3.00 moles Na

• 2.50 moles Na

A student performs a flame test on an unknown chloride salt, and a green photon of light is observed. The photon is assumed to have a wavelength of 5.2 x 10^-7 m. What is the frequency of the green photon emitted?

• 5.8 x 10^14 1/s

• 1.9 x 10^15 1/s

• 2.3 x 10^8 1/s

• 3.5 x 10^14 1/s