Periodic Table Key Terms

Periodic Table of Elements

A table that classifies elements by their physical and chemical properties; rows are called periods; columns are called groups or families.

Lewis dot Structure/Electron Dot Diagram

Diagram showing the number of valence electrons as paired and unpaired dots around an element

valence electrons

Electrons on the outermost energy level of an atom that participate in chemical bonding.

Metalloids

Elements found along the zig-zag line of the Periodic table, They have properties of both metals and nonmetals.

Representative Elements

Elements in groups 1 and 2 and 13-18 in the periodic table that include metals, metalloids, and nonmetals

Non-metals

Elements that are found to the right of the zig-zag line on the periodic table. They are dull, brittle, and poor conductors of heat and electricity.

Metals

Elements to the left of the zig-zag line on the Periodic table. They are shiny, ductile, malleable, and good conductors of heat and electricity.

Alkali Metals

Group 1, 1 valence electron, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium

Halogens

Group 17, 7 Valence Electrons. Most Reactive family of non-metals. Includes Fluorine, Chlorine, Bromine,Iodine, Astatine, Tennesine

Noble gases

Group 18 Elements, 8 Valence Electrons except Hydrogen with 2 Valence Electrons. All Colorless, Odorless gasses that are extremely non reactive. Includes Helium, Neon, Argon, Krypton, Xenon, Radon, Oganesson.

Alkaline earth metals

Group 2, 2 valence electrons harder than the alkali metals and are also less reactive: Beryllium, Magnesium, Calcium, Strontium, Barium, Radium

Dmitri Mendeleev

He is given credit for the first periodic table that was organized by increasing atomic mass.

Periods

Horizontal rows on the periodic table. Each period number = energy levels.

Post Transition Metals/Poor Metals

Metals found in groups 13-15 in the periodic table. Includes Aluminum, Galium, Indium, Thalium, Tin, Lead, and Bismuth

CHNOPS

Most common elements in all living matter. Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur

Oxidation number

Positive or negative number that indicates how many electrons an atom has gained, lost, or shared to become stable

Henry Moseley

Rearranged the periodic table by increasing atomic number. Is Responsible for the Modern Periodic Table design.

Actinide Series

Row Two of Rare earth elements/Inner Transition Metals. Include Elements 89-103

Lanthanide Series

Row one of Rare earth elements/Inner Transition Metals. Include Elements 57-71

octet rule

States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons

transition elements/metals

Those elements found groups 3-12 on the periodic table whose properties tend to be less predictable based simply on their position in the table.

Groups/Families

Vertical columns in the periodic table; contain elements with similar physical and chemical properties.

Rare earth elements/Inner Transition Metals.

the two rows of elements at the bottom, composed of elements 58-71 and 90-103, known as the lanthanides and actinides, respectively. They are at the bottom of the periodic table to save space.