Notes: Periodic Table Elements first classified by whom? Dimitri Mendeleev – Russian Scientist ( ) When was it first published? 1869 Categorized how? Listed in order of increasing molar mass What is the Periodic Law? The properties of the elements reoccur periodically when the elements are arranged in order by their atomic numbers.

METALS Non-METALS METALLOIDS Left side and center Right side On the “stair step line” (Al is not included because it always acts like a metal)

The Modern Periodic Table of Elements: How organized? By increasing atomic number (# of protons) Metallic elements – Left hand side – always lose electrons and form (+) ions Nonmetallic elements – Right hand side – gain electrons and form (-) ions Metalloids – Along the stair-step line – border of metals and non-metals Elements with both metallic and nonmetallic properties

Vertical columns are called groups. Elements are placed in columns by similar properties. Also called families

Vertical columns = groups or families -have similar chemical properties -elements have same charge (ions) The elements in groups have similar valence electron configurations in their ground states Horizontal rows= periods The properties are NOT similar in a period

Elements within the same row (or period) are in the same energy level

Alkali Metals Group 1

Group1 – Alkali Metals Elements = Li, Na, K, Rb, Cs, Fr Chemical properties = most highly reactive metals, kept under oil. Physical properties = metals, silver-grey, tend to be soft, light density Charge of ions = +1 End config: s 1 (1v.e) Reaction with water = violent and can catch on fire 2X + 2H 2 O → 2 XOH + H 2 * forms a basic solution

Alkaline Earth Metals Group 2

Group 2 – Alkaline Earth metals Elements = Be, Mg, Ca, Sr, Ba, Ra Chemical properties = very reactive, stored under oil (less reactive than Alkali metals) Physical properties = metals, silver- grey, tend to be soft, light density Charge of ions = +2_ End config:s 2 (2v.e) _

Transition Metals : short, center groups are collectively referred to as the transition elements Groups 3-12

Group 3-12 Transition Metals -They are given this name because it was believed that they chemically behaved mid-way between active metals and nonmetals. -Some common elements = Sn, Cu, Ag, Au, Zn, Fc, Mn, Cr, W Charge of ions = Multiple charges per element. Various charges throughout the set. End config: d 1 - d 10

Halogens Group 17

Group 17 - Halogens Elements = F, Cl, Br, I, At Chemical properties = Very reactive (most reactive nonmetals) Charge of ions = -1___ End config: s 2 p 5 (7 v.e.)

Noble Gases Group 18

Group 18 – Noble Gases Elements = He, Ne, Ar, Kr, Xc, Rn Chemical properties = very unreactive Charge of ions = 0 End config: s 2 p 6 (8 v.e.) Former name: Inert gases why inappropriate: inert means nonreactive, Although the noble gases are highly unreactive, under some circumstances(very rare)they do react.

Two long rows on bottom are collectively referred to as the “inner transition metals”

Lanthanide Series Actinide Series

Lanthanide Series Elements atomic # 58 to 71 Elements = Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho Located = located in the first of the two rows below the main periodic table. F-block Also classified as part of the inner transition metals Formerly named: Rare Earth Metals Incorrect because: not all of them are rare

Actinide Series Elements atomic # 90 to 103 Elements = Th, Pa, U, Np, Pu, Am, Cm Located = located in the second of the two rows below the main periodic table. F-block Also classified as part of the inner transition metals

Transuranium element – Element with atomic number greater than Uranium (92) Representative element – also know as Main group elements These elements include groups 1,2, and 13 – 18 s and p block Elements are either representative or transitional.