AP Chemistry : Atoms

Study concepts, example questions & explanations for AP Chemistry

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Example Questions

Example Question #1 : Atoms

Which of the following is not a subatomic particle?

Possible Answers:
Neutron
Electron
Alpha particle
Proton
Correct answer: Alpha particle
Explanation:

Protons, neutrons, and electrons are all subatomic particles. Alpha particles consist of 2 protons and 2 neutrons bound together in a particle. It is usually emitted during fission reactions. 

Example Question #1 : Atoms

Which of the following statements is true?

Possible Answers:

The nucleus of an atom is electrically neutral

Electrons are close in proximity to the atomic nucleus

Electrons are smaller in size than nucleons, but have equal charge

Electrons are larger than protons, which means they must have less charge than protons

Electrons are smaller than protons, which means they have less charge than protons

Correct answer:

Electrons are smaller in size than nucleons, but have equal charge

Explanation:

Electrons are notably smaller than nucleons (protons and neutrons), however, they have an equal amount of charge to protons. This is why an atom with the same amount of protons as electrons is considered electrically neutral.

The nucleus itself is positively charged, as the electrons are located relatively far away from the atomic center.

 

Example Question #2 : Atoms

What is the sum of the number of neutrons of the following atoms: (a) N15
(b) Ag109 (c) Si30

Possible Answers:

90

88

86

82

84

Correct answer:

86

Explanation:

In an atomic representation, the number of neutrons and protons is the upper number
and the number of protons is the lower number. If only one number is given, we can assume
that the number of protons is its atomic number. Therefore (a) 7 protons and 8 neutrons
(b) 47 protons and 62 neutrons (c) 14 protons and 16 neutrons. The total number is 86.

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