Chemistry: Electronic Configuration and Periodic Trends

Comprehensive review flashcards covering electron configurations, orbital diagrams, electromagnetic spectrum, history of the periodic table, and periodic trends.

How many electrons can a single orbital hold, and what are the required spin orientations for paired electrons?

Each orbital can hold a maximum of $2$ electrons, and paired electrons must have opposite spins (one clockwise $\uparrow$ and one counterclockwise $\downarrow$).

Based on this energy diagram of atomic shells and subshells, how do energy levels change as the principal quantum number ($N$) increases from $1$ outward?

Energy increases moving outward from shell $N=1$, which is closest to the nucleus and represents the lowest energy level.

According to Hund's rule, how must electrons be distributed across degenerate orbitals in a subshell?

Electrons must occupy each orbital singly with parallel spins before any orbital receives a second electron with an opposite spin.

What atomic process causes the emission of light and allows us to see color?

An electron absorbs energy from the outside and jumps from the ground state to an unstable excited state; when it jumps back down, it releases that energy in the form of light.

What is the complete order of the electromagnetic spectrum from lowest energy to highest energy?

Radio waves, Microwaves, Infrared (IR), Visible light ($\text{ROYGBIV}$), Ultraviolet (UV), X-rays, and Gamma rays (the most dangerous).

How did Dmitri Mendeleev and Henry Moseley differ in their organization of the periodic table?

Mendeleev arranged elements by increasing atomic mass, switched order based on chemical properties, and left gaps to predict undiscovered elements; Moseley arranged the modern table by atomic number ($1913$/$1915$), which eliminated mass-based inconsistencies.

What are the periodic trends for atomic radius across a period and down a group?

Atomic radius decreases across a period because additional protons and electrons stay in the same shell, creating stronger nuclear attraction that shrinks the atom; it increases down a group because additional electron shells increase the distance from the nucleus.

Which elements have the largest atomic radius and the highest ionization energy, respectively?

Francium ($Fr$) has the largest atomic radius and lowest ionization energy, while Helium ($He$) has the smallest atomic radius and highest ionization energy.

What is ionization energy (IE), and how does it trend across a period and down a group?

Ionization energy is the energy required to remove an outermost (valence) electron; it increases across a period because smaller atoms hold valence electrons more tightly, and it decreases down a group because greater distance reduces nuclear attraction.

What is electronegativity / electron affinity (EN / EA), and how does it vary across the periodic table?

It is the attraction for electrons or the energy released when an electron is added to an atom; it increases across a period due to greater nuclear attraction and decreases down a group as atoms become larger.

What are the general reactivity trends for metals and non-metals on the periodic table?

Metal reactivity increases down and to the left (with Francium, $Fr$, being the most reactive metal); non-metal reactivity increases up and to the right (with Fluorine, $F$, being the most reactive non-metal, excluding inert noble gases).

According to the video lecture notes, which metal is liquid at room temperature, which melts in your hand, and which has the highest melting point?

Mercury is liquid at room temperature, Cesium melts in the hand, and Tungsten has the highest melting point.

How do alkali metals behave physically and chemically when freshly cut?

They are soft metals that appear shiny when cut, but react readily with $O_2$ and blacken; their reactivity increases and reactions proceed faster going down the group.

What are the abbreviated noble gas electron configurations of Cobalt ($Co$) and Radium ($Ra$)?

Cobalt ($Co$) is $[Ar]\,4s^2\,3d^7$ and Radium ($Ra$) is $[Rn]\,7s^2$.

What is the outer electron configuration of neutral Iron ($Fe$, atomic number $26$)?

$[Ar]\,4s^2\,3d^6$.

What are five metallic properties recorded in the periodic table notes?

Shiny, malleable, ductile, solid, and conductive.

What are the family names for Group 1, Group 2, Group 17, and Group 18 on the periodic table?

Group 1 are Alkali metals, Group 2 are Alkaline-Earth metals, Group 17 are Halogens, and Group 18 are Noble gases.

What are the noble gas shorthand electron configurations for the strontium ion ($Sr^{2+}$) and selenide ion ($Se^{2-}$)?

Both $Sr^{2+}$ and $Se^{2-}$ achieve the stable noble gas configuration of Krypton, represented as $[Kr]$ (or $[Ar]\,4s^2\,3d^{10}\,4p^6$).