Atomic Concepts Review

Which statement describes a concept included in the wave-mechanical model of the atom?

• Electrons travel in fixed orbits

• Neutrons are in shells outside the nucleus

• Protons are in orbitals outside the nucleus

• Electrons are in orbitals outside the nucleus

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NGSS.HS-PS4-3

The mass of an electron is

• equal to the mass of a proton

• equal to the mass of a neutron

• greater than the mass of a proton

• less than the mass of a neutron

The results of the gold foil experiment led to the conclusion that an atom is

• mostly empty space and has a small, negatively charged nucleus

• mostly empty space and has a small, positively charged nucleus

• a hard sphere and has a large, negatively charged nucleus

• a hard sphere and has a large, positively charged nucleus

There are 3 isotopes of oxygen: O-16, O-17, and O-18. These neutral atoms contain

• equal numbers of protons, neutrons, and electrons

• equal numbers of protons and electrons, but different numbers of neutrons

• equal numbers of protons and neutrons, but different numbers of electrons

• different numbers of protons, neutrons, and electrons

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NGSS.HS-PS1-8

What is the mass number of the atom shown in the image?

• 9

• 10

• 19

• 28

All isotopes of neutral atoms of sodium have

• 11 protons and 12 neutrons

• 12 protons and 11 neutrons

• 11 protons and 11 electrons

• 12 protons and 12 electrons

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NGSS.HS-PS1-8

Which notations represent atoms that are isotopes of each other?

• C-14 and N-14

• O-16 and O-18

• I-131 and I-131

• Rn-222 and Ra-222

Element X has two isotopes. If 72.0% of the element has an isotopic mass of 84.9 amu and 28.0% has an isotopic mass of 87.0 amu, the average atomic mass of element X is numerically equal to

• (84.9 x 72.0) + (87.0 x 28.0)

• (84.9 + 0.720) x (87.0 + 0.280)

• (84.9 x 0.720) + (87.0 x 0.280)

• (84.9 - 72.0) x (87.0 - 28.0)

If the atomic number of a neutral element is 35, and its nucleus contains 40 neutrons, which of the following is correct?

• The atom is bromine, and it has 35 electrons

• The atom is bromine, and it has a mass number of 40

• The atom is zirconium, and it has a mass number of 75

• The atom is zirconium, and it has 40 electrons

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NGSS.HS-PS1-1

An excited potassium atom emits a specific amount of energy when one of its electrons moves from

• the first shell to the fourth shell

• the second shell to the fourth shell

• the fourth shell to the fifth shell

• the fourth shell to the second shell