CHM1045 Exam 2 Flashcards (P1)

Electronic structure and periodic properties of elements.

Schrödinger's wave equation:

An equation that incorporates both the wave-like and particle-like behaviors of the electron. His work led to the quantum/wave mechanics approach to dealing with subatomic particles, particularly the electron.

What four quantum numbers is the quantum mechanical model of the state of an electron described by?

Principal quantum number (n), Angular momentum quantum number (l), Magnetic quantum number (ml), Spin quantum number (ms).

What does the principal quantum number describe?

The energy level on which the orbital resides; values = any non-zero positive integer.

What does the angular momentum number describe?

The shape of the orbital; values = 0 to n-1.

What does the magnetic quantum number describe?

The orientation of the orbital; values = -l <= ml <= ml.

What does the spin quantum number describe?

The direction of electron spin; values = +1/2 & -1/2.

What does Pauli's Exclusion Principle state?

In an atom, no two electrons can have the same set of four quantum numbers.

What is a shell?

A collection of orbitals with the same principal quantum number (n).

What is a subshell?

A collection of orbitals with the same values of n and l.

What is an orbital?

A place in an atom where an electron is likely to be found.

What are the traits of the s orbital?

Spherical, l value = 0, ml value = 1 (1 orientation).

What are the traits of the p orbital?

Dumbbell-like, l value = 1, ml values = -1, 0, 1 (3 orientations).

What are the traits of the d orbital?

Four-leaf clover shaped, l value = 2, ml = -2, -1, 0, 1, 2 (5 orientations).

What are the traits of the f orbital?

Complicated shape, l value = 3, ml values = -3, -2, -1, 0, 1, 2, 3, (7 orientations).

What is electron spin?

Fundamental property of electrons describing intrinsic angular momentum value.

What is the energy level?

The distance of an electron from the nucleus, represented by n.

What happens in an electron as the principal quantum number increases?

The size and energy of atomic orbitals increase, and because larger n values are further away from the nucleus, the attraction between the nucleus and an electron becomes weaker and the orbital's energy is higher (less stable).

What are degenerate orbitals?

Orbitals residing on the same energy level.

What is electron configuration?

The way electrons are distributed in an atom, starting with the lowest possible quantum numbers first (ground state).

What is the Aufbau principle and the n+1 rule?

Electrons occupy the lowest energy orbitals available before filling higher energy orbitals; the orbital with the lesser n+1 value fills first, and if this value is the same for 2 orbitals, the one with the lesser n value fills first.

What are orbital diagrams?

Visual representations of electron configuration, showing the individual orbitals and the pairing arrangement of electrons.

What is the s block of the periodic table?

Groups 1 & 2 plus helium.

What is the p block of the periodic table?

Groups 13 to 18, except helium.

What is the d block of the period table?

Groups 3 to 12.

What is the f block of the periodic table?

The 2 bottom rows (lanthanides and actinides); rows 6 and 7 respectively.

What is Hund's rule?

Electrons will occupy empty orbitals of the same energy level one at a time before pairing up.

What elements do the s & p blocks correspond to?

Main group elements, representative elements.

What elements does the d block correspond to?

Transition elements.

What elements does the f block correspond to?

Inner transition elements.

Why was Mendeleev's periodic table more accepted than Meyer's?

Because his table had predictive abilities.

What is the Periodic Law, and what does it mean?

The properties of elements are periodic functions of their atomic numbers; When elements are arranged by increasing atomic number, their physical and chemical properties repeat at regular intervals.

What are periods in a periodic table?

Horizontal rows.

What are the properties of periods in a periodic table?

Period number corresponds to n, and elements in the same period have valence electrons in the same outermost shell.

What are groups in a periodic table?

Vertical columns.

What are the properties of groups in a periodic table?

Elements of the same group have the same number of valence electrons, and form bonds of the same type.

What are the classifications of main group/representative elements?

Alkali metals (group 1), Alkaline earth metals (group 2), Pnictogens (group 15), Chalcogens (group 16), Halogens (group 17), and Noble gases (group 18).

What are the properties of metals?

Shiny, malleable, conductive, low ionization energies/forms cations easily.

What are the properties of nonmetals?

Dull, brittle, nonconductive, high ionization energies/forms anions easily.

What are the properties of metalloids?

Moderately conductive, properties of both metals and nonmetals.

What are periodic properties?

Size, ionization energies, and electron affinities.

How does (covalent) size change on the periodic table?

Atomic size decreases from left to right and increases from top to bottom.

How does (ionic) size change on the periodic table?

A cation is always smaller than its neutral parent atom, and an anion is always bigger than its neutral parent atom. Therefore, cation<neutral<anion.

What does the term isoelectric refer to?

Atoms and ions with the same electron configuration.

How does (isoelectronic) size change on the periodic table?

Isoelectronic size decreases from left to right and increases from top to bottom.

What is ionization energy?

A measure of the difficulty in removing an electron from an atom or ion, or the tendency of an atom or ion to surrender an electron.

How do successive ionization energies work?

Successive ionization energies for an element always increase; a large enough increase in successive ionization energies signifies the removal of core electrons.

How does ionization energy change on the periodic table?

Ionization energy increases across a period, and decreases down a group.

What is electron affinity?

The energy charge for the process of adding an electron to a gaseous atom to form an anion.

What aspects of electron affinity are element-dependent?

Whether the process is endothermic or exothermic, and whether energy is released when the gaseous atom accepts the electron (Negative EA) or energy is required for the gaseous atom to accept an electron (Positive EA).

How does electron affinity change on the periodic table?

Electron affinity increases across a period (with the exceptions of groups 2A, 5A, and 8A) and does not change much down a group.