AP Chemistry : The Periodic Table

Study concepts, example questions & explanations for AP Chemistry

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Example Questions

Example Question #81 : Understand Basic Chemistry

Sodium will react with oxygen and form an ionic compound. Which of the following is false concerning this interaction?

Possible Answers:

The electrons are not equally shared between sodium and oxygen

In this compound, oxygen is the anion while the two sodium atoms are defined as cations

Both oxygen and the two sodiums are given stable octets by creating the ionic compound

The ionic compound has an overall neutral charge

Sodium has a higher electronegativity than oxygen, causing it to give its electron to oxygen

Correct answer:

Sodium has a higher electronegativity than oxygen, causing it to give its electron to oxygen

Explanation:

Electronegativity is defined as the tendency of an atom to attract an electron in a bond that it shares with another atom. Because oxygen wants to receive two elctrons, while both sodiums wish to lose one electron, oxygen has a higher electronegativity than sodium. Typically, electronegativity can be seen as increasing as you go to the top right of the periodic table. For example, fluorine has a higher electronegativity than nitrogen.

Example Question #1 : The Periodic Table

What is the energy required to form a gaseous cation from a gaseous atom?

Possible Answers:

Free energy

Electronegativity

Kinetic energy

Ionization energy

Correct answer:

Ionization energy

Explanation:

This is the correct definition of ionization energy. By removing an electron from an atom, a cation is produced.

Example Question #2 : The Periodic Table

Why can some atoms exceed the octet rule?

Possible Answers:

They have d-orbitals where the extra electrons can go

They are nonmetals

They are very electronegative. 

They do not exhibit any intermolecular forces

Correct answer:

They have d-orbitals where the extra electrons can go

Explanation:

Atoms in the third period and above have d-orbitals that can hold up to 10 elecrons. This is what allows for atoms to exceed the octet rule.

Example Question #111 : Ap Chemistry

What properties do metallic compounds have that others lack?

Possible Answers:

Conductivity in the liquid phase

Conductivity in the solid phase

Solid at room temperature

Brittle lattice structure

Correct answer:

Conductivity in the solid phase

Explanation:

Metallic compounds have unique properties due to their electron motility. In metals, electrons are able to move freely around and between atoms. In non-metals, electrons are more tightly bound to the nucleus due to increased nuclear positive charge and decreased atomic radius. The fluidity of electrons in metals allows them to conduct electric charge.

Metals are generally non-brittle. Metals are solids at room temperature and conduct electricity in the liquid phase, but they share these properties with a number of non-metal compounds as well.

Example Question #16 : Elements And Atoms

Why are the transition metals good conductors of electricity?

Possible Answers:
Most transition metals have 3d electrons that only partially fill the valence band
They lose electrons from p orbitals
They have small band gaps
The energy levels of the atomic orbitals are close together
They have no valence electrons
Correct answer: Most transition metals have 3d electrons that only partially fill the valence band
Explanation:

Transition metals have only partially filled valence bands. Thus, the electrons can move among the d orbitals, and this electron flow allows the transition metals to be good conductors of electricity. 

Example Question #17 : Elements And Atoms

Which of the following does not determine the length of an element's atomic radius?

Possible Answers:

Number of valence electrons

Effective nuclear charge that electrons experience

Number of electron shells

Number of neutrons

Correct answer:

Number of neutrons

Explanation:

The number of neutorns is the only thing out of the answer choices that does not impact an element's atomic radius. Since neutrons have no charge, they do not impact the attractive forces between electrons and protons.

Example Question #6 : The Periodic Table

Which of the following atoms is least likely to have a full octet when it is part of a molecule?

Possible Answers:

Cl

C

O

B

Correct answer:

B

Explanation:

B (boron) is one of the atoms known for making fewer than 4 covalent bonds, and therefore not filling its octet. C (carbon) always makes 4 bonds, while O (oxygen) and Cl (chloride) are also known for having full octets.

Example Question #1 : The Periodic Table

Which of the following elements behaves the most like calcium?

Possible Answers:

Potassium

Bromine

Scandium

Strontium

Rubidium

Correct answer:

Strontium

Explanation:

Strontium is in the same group as calcium in the periodic table, which means that they both have the same number of valence electrons; they are both alkaline earth metals with two valence electrons. This is one of the most important chemical properties, as it dictates how an element will react. Like calcium, strontium will lose its two valence electrons easily to form ionic compounds.

Example Question #1 : The Periodic Table

Which of the following best explains effective nuclear charge (Zeff)?

Possible Answers:

An electrostatic attraction between valence electrons and the nucleus

The charge of an electron

The atomic mass of an element

The number of protons and neutrons of an element

The charge of any nucleon

Correct answer:

An electrostatic attraction between valence electrons and the nucleus

Explanation:

The correct answer choice is an accurate explanation of effective nuclear charge. Since electrons are negatively charged, they are attracted to protons, which are positively charged. Protons are located in the nucleus of an atom.

Example Question #9 : The Periodic Table

Which of the following elements are classified as a non-metal?

Possible Answers:

Rn

W

Na

Be

Hg

Correct answer:

Rn

Explanation:

Rn is radon, a noble gas, which is not a metal. As a rule, elements to the left are metals, elements to the right are non-metals. The barrier would be the elements that are immideately to the right of the transition metals

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