Unit 3: Periodic Table and Electrons Study Guide

Vocabulary flashcards covering element classifications, groups, periodic trends, electron configurations, and subshells based on the Unit 3 study guide.

Metals

Elements that are shiny (lustrous), malleable, ductile, and excellent conductors of heat and electricity, with most being solids at room temperature.

Nonmetals

Elements that are generally dull, brittle, and poor conductors (insulators), which can exist as solids, liquids, or gases.

Metalloids

Elements located along the 'stair-step' line that have properties intermediate between metals and nonmetals, such as semiconductors like Silicon.

Periods

The 7 horizontal rows on the periodic table where elements have the same number of electron shells (energy levels) but different chemical properties.

Groups

The 18 vertical columns on the periodic table where elements share the same number of valence electrons and exhibit similar chemical properties.

Alkali Metals

Group 1 highly reactive metals with 1 valence electron that form $+1$ ions.

Alkaline Earth Metals

Group 2 reactive metals with 2 valence electrons that form $+2$ ions.

Transition Metals

Groups 3-12 elements that form various oxidation states and often colored compounds.

Boron Family

Group 13 elements containing 3 valence electrons, 1 metalloid (Boron), and 4 metals.

Carbon Family

Group 14 elements containing 4 valence electrons and a mix of nonmetals (Carbon), metalloids, and metals.

Nitrogen Family

Group 15 elements containing 5 valence electrons; also known as pnictogens.

Oxygen Family

Group 16 elements containing 6 valence electrons; also known as chalcogens.

Halogens

Group 17 elements containing 7 valence electrons; they are the most reactive nonmetals and form $-1$ ions.

Noble Gases

Group 18 elements with a full outer energy level that are extremely stable and unreactive.

Atomic Radius

Periodic property that decreases from left to right as more protons pull electrons closer, and increases moving down as energy levels increase; Helium is the smallest and Francium is the biggest.

Cations

Positively charged ions that lose an energy level and are smaller than the original atom.

Anions

Negatively charged ions that gain electrons (increasing repulsion) and are larger than the original atom.

Ionization Energy

The amount of energy required to create an ion (cation); increases from left to right and decreases moving down.

Electronegativity

The ability of an atom to attract electrons while bonded to another atom; increases from left to right and decreases moving down, with Francium being the lowest and Fluorine being the highest.

Aufbau Principle

Orbital rule stating that electrons fill the lowest energy orbitals first (1s, then 2s, etc.).

Pauli Exclusion Principle

Orbital rule stating that an orbital can hold a maximum of 2 electrons with opposite spins (arrows).

Hund's Rule

Orbital rule stating that within a subshell (like 2p), electrons fill each orbital singly before pairing up.

Valence Electrons

Electrons located in the highest energy level ($n$); determined by the group number for main-group elements.

Oxidation Numbers

The charge an atom would have if all bonds were ionic.

s Subshell

A subshell type containing 1 orbital that can hold a maximum of 2 electrons.

p Subshell

A subshell type containing 3 orbitals that can hold a maximum of 6 electrons.

d Subshell

A subshell type containing 5 orbitals that can hold a maximum of 10 electrons.

f Subshell

A subshell type containing 7 orbitals that can hold a maximum of 14 electrons.