Chapter 3 - Atomic and Molecular Structure

All matter is composed of what?

Atoms

How are compounds formed?

Compounds are formed by whole number ratios of two or more atoms

What is the term for the fundamental unit of matter?

Atom

What is a chemical reaction a rearrangement of?

A rearrangement of atoms

Are protons heavier or lighter than electrons?

Protons are heavier

Are neutrons heavier or lighter than protons?

Neutrons are heavier ever slightly

Which two subatomic particles make up most of the atom's mass?

Protons and neutrons

What does atomic number refer to?

Number of protons found in the atom of that specific element

What is the atomic number useful for?

It acts as a tool for identifying the identity of an unknown element, as this number remains constant across all isotopes of an element (e.g. all carbon atoms have 6 protons)

What does atomic mass refer to?

The weighted average of an element based on its isotopes

What are cations?

Atoms that have lost one or more electrons to become positively charged

What are anions?

Atoms that have gained one or more electrons to become negatively charged

Do valence electrons have higher or lower energy compared to electrons closer to the nucleus?

Higher energy

The modern quantum theory has replaced which outdated model?

The Bohr model (described electrons as following defined circular orbits around nucleus)

How does the modern quantum theory describe the pathway of electrons?

Electrons occupy in a 'cloud of electrons' surrounding the nucleus

What does the Heisenberg uncertainty principle describe?

It is impossible to perfectly find both the momentum and the location of an electron in an atom at a given time. In other words, you can figure out one or the other but not both

What does principle quantum number refer to?

Represents the main energy level occupied by electrons

What are the possible values for principle quantum number?

Must be positive integer number, equal or greater than 1

The maximum number of electrons that an electron shell can hold is given by what formula?

2n²

What does azimuthal quantum number refer to?

Describes the shape of the subshells or the orbital shape within each principle energy level

What are the possible values for azimuthal quantum number?

Between zero and the value of the principle quantum number minus 1

If a principle quantum number is 1, what are the potential azimuthal quantum numbers?

Only 0

If a principle quantum number is 4, what are the potential azimuthal quantum numbers?

0, 1, 2, and 3.

What azimuthal quantum number is associated with a 's' subshell?

0

What azimuthal quantum number is associated with the 'p' subshell?

1

What azimuthal quantum number is associated with the 'd' subshell?

2

What azimuthal quantum number is associated with the 'f' subshell?

3

How many electrons can be held in the 's' subshell?

2

How many electrons can be held in the 'p' subshell?

6

How many electrons can be held in the 'd' subshell?

10

How many electrons can be held in the 'f' subshell?

14

What does the magnetic quantum number refer to?

Describes the orientation of orbitals in space

What are the possible values for magnetic quantum number?

Number ranges between the negative and positive magnitude of the azimuthal number

What magnetic quantum numbers are possible for a 'p' subshell?

-1, 0, and 1

What magnetic quantum numbers are possible for a 'f' subshell?

-3, -2, -1, 0, 1, 2, 3

What does the spin quantum number refer to?

Describes the angular momentum of an electron

What are the possible values for spin quantum number?

+1/2 or -1/2

What does the Pauli exclusion principle state?

No two electrons in an atom can have the exact set of four quantum numbers

What does Hund's rule state?

Within a given subshell, orbitals are filled such that the maximum number of half-filled orbitals are obtained. This is why you often see half filled 4s orbitals and half filled 3d orbitals

What does the Aufbau principle state?

Electrons will first occupy lower-energy orbitals before filling higher-energy orbitals

Are covalent bonds weaker or stronger than ionic bonds?

Weaker

Are covalent compounds more likely to have higher melting and pointing points compared to ionic compounds?

No, covalent compounds are more likely to have lower melting and boiling points due to weak covalent bonds

What does bond length refer to?

Distance between nuclei of each atom involved in a bond

What does bond energy refer to?

Energy needed to break a bond between two atoms

Does the sharing of electrons in a covalent bond have to be equal?

No. Electrons can be shared unequally in covalent bonds, leading to polarity

What is involved in forming ionic bonds?

It involves the complete transfer of electrons from the less electronegative atom to the more electronegative atom

What are the three types of intermolecular forces?

London dispersion force (aka Van der Waals), dipole-dipole, and hydrogen bonds

What is required to form a hydrogen bond?

Hydrogen attached to a very electronegative atom (such as oxygen, nitrogen, or fluorine)

What type of bond results from parallel overlap of orbitals?

Pi bond

What type of bond results from head-to-head overlap of orbitals?

Sigma bond

Which bonds are involved in a double bond?

One sigma bond and one pi bond

Which bonds are involved in a triple bond?

One sigma bond and two pi bonds

Between sigma and pi bond, which allows for free rotation at the axis?

Sigma allows free rotation at axis while pi bond does not

What is the bond order of a single bond?

One

What is the bond order of a triple bond?

Three

As the bond order increases, what happens to bond length and bond strength?

Length decreases and strength increases

Does bond strength increase or decrease going down a column on the periodic table?

Decrease. As atomic radii increases, bond length increases resulting in decreased bond strength