Organization of the Periodic Table Classifying the Elements

Dmitrii Mendeleev Organized his periodic table by the elements increasing atomic mass

Modern Periodic Table The modern periodic table is organized by increasing atomic number

Periodic Law The Periodic Law states that when elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

Periods The horizontal rows 1 – 7 periods The atomic number increases across a period from left to right

Groups The vertical columns of the periodic table (1-18) All elements in a group have the same number of valence electrons All the elements in a group have very similar chemical and physical properties

Elements can be classified as metals, non-metals or metalloids

Metals Good conductors of heat and electricity High luster (shiny) Malleable and ductile Solid at room temperature (except for Mercury) Most elements are metals – 80%

Non-metals Poor conductors of heat and electricity Vary in properties, many are gases, some are solids and liquid Solid forms are dull and brittle

Metalloids Share properties of both metals and nonmetals A metalloid may behave as a metal under some conditions, but the same metalloid may behave as a nonmetal under other conditions Ex: May be a good conductor but brittle

Metals (left side) Non-metals (right side) Metalloids (staircase) Metals = Green Non-metals = Blue Metalloids = Pink

Label the following elements as a metal, non-metal, or metalloid C = carbonNon-metal Mg = magnesiummetal Bi = bismuthmetal Si = siliconmetalloid

The periodic table consists of Representative Elements and Transition Elements (Transition Metals and Inner Transition Metals)

Representative Elements Found in groups and groups 13 – 18 Wide variety of properties that represent the table as a whole Represent each category of metals, nonmetals, and metalloids Represent each state of matter solids, liquids and gasses A 4A 5A 6A 7A 1A1A 22A22A

Transition metals Groups (middle of the periodic table) These metals are solid at room temperature (except for Mercury)

Inner transition metals Found underneath the periodic table Lanthanide series - period 6 Actinide series - period 7 These metals are solid at room temperature Inner Transition Metals

Representative Elements: yellow Nobel Gasses: purple Transition Metals: orange Inner Transition Metals: green

Important Groups There are groups of elements in the periodic table that are given special names Elements in a group share similar chemical and physical properties

Alkali Metals Li, Na, K, Rb, Cs, Fr Group 1 (1A) – excluding Hydrogen 1 valence electron Very unstable and highly reactive Extremely soft metals All have low densities, melting and boiling points.

Alkaline Earth Metals Be, Mg, Ca, Sr, Ba, Ra Group 2 (2A) 2 valence electrons Very reactive Bond and lose 2 electrons

Halogens F, Cl, Br, I, At Group 17 (7A) 7 valence electrons Bond and gain 1 more electron to make their outer energy level full. A halogens bond with alkali metals to form a salt

Noble Gasses Most stable of the elements (non-reactive) Outermost energy level or shell is full, so they do not naturally bond with other elements Share properties like high densities, high melting points, colorless, odorless, and tasteless He, Ne, Ar, Kr, Xe, Rn Group 18 (8A) 8 valence electrons

Lanthanide Series “Rare-Earth elements” Found on the top row of the inner transition metals Named from element Lanthanum (La) atomic number 57 - common properties

Actinide Series Radioactive metals Found on the bottom row of the inner transition metals Named after the element Actinium (Ac) atomic number 89 - common properties