The Periodic Table http://www.skanschools.org/webpages/rallen/atomic_theory_.cfm?subpage=1179288

History of the Table Dmitri Mendeleev (Russia) The 1st chemist to arrange the newly found elements into a table/usable manner Arranged them according to atomic mass This caused gaps or periodic intervals being out of order History of the Table

History of the Table Henry Moseley (England) Used X-ray spectra to prove the existence of the protons Arranged the table by atomic number (# of protons) Gaps are now gone Modern day periodic table History of the Table

Elements in the periodic table are periodic functions of their atomic number Periodic Law

1. as you move down a group (column), you add 1 principal energy level or electron shell 2. as you move across a period (row), you add 1 proton to the nucleus, and 1 electron to the valence shell Periodic Law

3. the maximum number of valence electrons any element can have is eight Any element with 8 valence electrons signifies the end of a period The next element will be the start of a new period with 1 valence electron PERIOD ( ROW) Periodic Law

4. the number of valence electrons determines the number of bonds an atom can form Periodic Law

5. the number of bonds an element can form determines the element’s chemical properties 6. all elements in the same group have the same number of valence electrons They also have similar chemical properties Group (column) Periodic Law

Arrangement of the Periodic Table The table is made up of periods and groups Periods= horizontal rows (run left to right) Groups= vertical columns (run up & down) Octet= full valence shell (8 electrons) Except for period 1 elements 2 electrons make a full valence shell Arrangement of the Periodic Table

The Groups Group 1 Alkali metals (Family) All have 1 valence electrons Easily lose their one electron to become +1 ion Extremely reactive  never found alone in nature Contains most reactive metal Francium-which is very rare Cesium is the second most reactive The Groups

The Groups Group 2 Alkaline Earth Metals (Family) All have 2 valence electrons Prefer to lose their two electrons to become +2 Fairly reactive-never found alone in nature The Groups

The Groups Groups 3-12 Transition Metals Found in the middle of the table (D block) Form colored ions in solution Tend to be unpredictable almost every transition metal can form different #s of bonds depending on what other elements or polyatomic ions are present Have multiple oxidation states Least reactive group of metals Most likely to be found uncombined in natured Ex. Cu is bright blue when dissolved in water Polyatomic ion- molecular ion two or more atoms bonded together Oxidation state- the degree of oxidation (how many electrons an atom can lose) The Groups

The Groups Groups 13-16 BCNO (not a single group) Miscellaneous groups Metals, nonmetals, & metalloids found along the staircase Many different properties The Groups

The Groups Group 17 Halogens (family) 7 valence electrons Like to gain 1 electron to become ions with -1 charge Form salts/compounds called halides Contains the most reactive nonmetal: Fluorine (F) All nonmetals Three states of matter found in group: Solid, liquid, gas The Groups

The Groups Group 18 Noble Gases (Family) Unreactive or inert Octet Most stable group: exist alone in nature Exception to the octet is He ) only has 2 valence electrons The Groups

The Groups Hydrogen not officially part of a group Both a nonmetal and a gas Can be seen as H2 or H+ or H- The Lanthanide/Actinide Series- two rows on bottom of the table Detached Elements 58-79 Belong to nonmetals Lanthanide Rare earth elements Actinide- radioactive due to instability The Groups

The Periodic Table The Staircase 1. metals: make up most of the table Left of or below “staircase”-except H All solids (except Hg) Must have all four properties of a metal 1. malleable (can be hammered/molded into sheets) 2. ductile (can be drawn/pulled into wire) 3. have luster (are shiny when polished) 4. good conductors (allow heat & electricity to flow through them) Due to sea of mobile valence electrons Like to lose electrons to form positive ions The Periodic Table

The Periodic Table 2. Nonmetals Right of or above the staircase Mostly gases and solids @STP-except Br Not malleable/ductile; brittle (shatter easily) Lack luster (dull) Non or poor conductors Like to gain electrons to form negative ions May have one or zero properties of a metal The Periodic Table

The Periodic Table 3. Metalloids (aka semi metals) Have two properties of a metal Along staircase (between metals and nonmetals ) Except Al The Periodic Table

Phases of Matter at STP Solids (s)- most elements are solids at STP Definite volume Definite shape Phases of Matter at STP

2. Liquids (l) only two elements at STP (Br & Hg) Definite volume Takes the shape of the container Phases of Matter at STP

Phases of Matter 3. Gases (g)- H, N, O, F, Cl & noble gases no definite volume Fill their container 4. Aqueous (aq) a STATE of matter which one substance (a solute) is dissolved in another (solvent); a solution Not a phase Homogenous mixture Ex. Na Cl Phases of Matter

Elements that are unstable alone in nature pair up in order to fill their valence shells Both need the same number of electrons to fill the valence shell Diatomic Elements

Diatomic Elements Contain 2 identical atoms 7 of them Include N2, O2, F2, Cl2, Br2, I2 and H2 Diatomic Elements

1 of 2 or more different forms of an element in the same phase, but with different formulas and different physical/chemical properties Ex. O2 (oxygen) and O3 (ozone) Carbon graphite (pencils) and diamonds Allotrope

Periodic Trends As you move across a period 1. nuclear charge increases a. additional proton b. Pulls electron cloud in more tightly 2. shielding does not increase a. kernel electrons interfere with attraction between protons in the nucleus and the valence electrons b. Every element in the same period/row has the same number of kernel electrons Shielding draws the electrons toward the nucleus Periodic Trends

Periodic Trends As you move down a group 1. nuclear charge increases but 2. Shielding increases Additional orbital/energy level means more kernel electrons (-) to interfere with the attraction between the protons and the valence electrons Valence electrons are able to drift further from the nucleus Periodic Trends

Atomic Radius ½ the distance between neighboring nuclei of a given element Periodic Trends

Periodic Trends Moving down a group Moving across a period Atomic radius increases Adding energy levels to the outside of the atom take up more space Moving across a period Atomic radius decreases Nuclear charge is increasing Same # of energy levels, no increase in shielding Periodic Trends

Periodic Trends Ionic Radius- radius of ions Nonmetals gain electrons radius increases Same nuclear charge pulling on more e- Electrons outnumber protons Electrons drift further away from the nucleus Periodic Trends

Periodic Trend Metal lose electrons  radius decreases Same nuclear charge pulling on less electrons Protons outnumber electrons Electrons are pulled closer to the nucleus Periodic Trend

Isoelectronic series: atoms and ions that have the same number of total electrons Elements gain or lose electrons in order to attain the electron configuration of the nearest noble gas All members of an isoelectronic series have the same noble gas configuration Periodic Trends

Periodic Trends Electronegativity Desire to gain electrons Nonmetals gain electrons to achieve full octet  high electronegativity Metals lose electrons to achieve full octet low electronegativity Periodic Trends

Periodic Table Electronegativity 0.0 to 4.0 Most electronegative element Fluorine Least electronegative element cesium or francium Periodic Table

Periodic Trend Going across a period, electronegativity increases Increased nuclear charge Shielding does not increase Going down a group, electronegativity decreases Increased shielding Periodic Trend

Ionization Energy amount of energy needed to remove the most loosely bound electrons from an atom/ion (in the gas phase) X + energy  X+ + e- Periodic Trends

Periodic Trends Going across a period, ionization energy increases Increased nuclear charge Shielding does not increase Going down a group, ionization energy decreases Increased shielding Periodic Trends

Ability or tendency of an element to go through a chemical change or (react with another element) Metals are loser when it comes to electrons Nonmetals gain when it comes to electrons Reactivity

Reactivity Metals (francium most reactive) Going across a period, reactivity decreases Increased nuclear charge Shielding does not increase Going down a group, reactivity increases Increased shielding Reactivity

Reactivity Nonmetals most reactive Fluorine Going across a period, reactivity increases (until you reach the noble gases) Increased nuclear charge Shielding does not increase Going down a group, reactivity decreases Increased shielding Reactivity