Chemistry Unit 3 - Periodic Table Vocabulary

Atomic Number

Number of protons in an element, the identity of an element

Electron Configuration

The order of electrons within orbitals

Valence Electrons

The outermost electron shell; highest energy electrons

Period

Row; describes the principal energy level (number of shells)

Group

Column; elements in the same group have similar chemical properties

Octet Rule

Any element can have a maximum of 8 valence electrons; stable e- config

Chemical Properties

Properties an element exhibits when reacting

Alkali Metals

Group 1 metals, all have one valence electron

Alkaline Earth Metals

Group 2 metals, all have 2 valence electrons

Transition Metals

Groups 3-12, form colored ions in solution

Halogens

Group 17 nonmetals, have 7 valence electrons

Noble Gases

Group 18 nonmetals, have a stable valence shell (8 is great)

Diatoms

Elements that exist as pairs, Br I N Cl H O F

Lewis Dot Diagram

Diagram that shows the element symbol with valence electrons surrounding

Oxidation State

Charge of an element, due to gaining/losing electrons for stability

Isoelectronic Elements

Different elements that have the same electron configuration

Metals

Most of the periodic table, to the left of the staircase EXCEPT H; malleable, ductile, lustrous, conductive

Nonmetals

To the right of the staircase; brittle, dull, insulators

Metalloids

On the staircase EXCEPT Al; may have 1-2 properties of metal

Electronegativity

The desire to gain or pull an electron (F is highest)

First Ionization Energy (FIE)

The amount of energy needed to pull an electron away (high in top right)

Atomic Radius

The distance between the nucleus and the valence shell of an electron

Ionic Radius

Gain electrons = bigger; Lose electrons = smaller

Reactivity

Describes the relative ability to undergo a reaction; F is most reactive nonmetal; Fr is most reactive metal; Noble gases are inert (don’t react)

Phase

Solid, liquid, or gas; @STP most are solid, BeaR HuG for liquids (Br and Hg), gases are H, N, O, F, Cl and group 18

Allotrope

Different crystal structures of the same element that have different chemical and physical properties (diamond vs graphite)