Periodic Table

Mendeleev vs. Modern Periodic Table Mendeleev organized his periodic table by increasing atomic mass The modern periodic table is organized by increasing atomic number This arrangement reflects the periodic recurrence of similar properties as the atomic number increasesatomic number

Groups in the Periodic Table Groups are the vertical columns in the periodic table (also know as families) Elements in the same group will have similar chemical and physical properties (because they have the same number of valence electrons)

Periods in the Periodic Table Periods are the horizontal rows in the periodic table All of the elements in a period have the same number of atomic orbitals. atomic orbitals As you proceed from left to right on The Periodic Table, a proton and an electron is added

The Element Song

Classes of Elements 3 main types of elements: 1.Metals 2.Nonmetals 3.Metalloids

Properties of Metals Good conductors of heat and electricity Luster (shiny) Ductile (can be drawn into thin wires) Malleable (can be hammered into a thin foil or into shapes)

Properties of Nonmetals Properties opposite of Metals Poor conductors of heat and electricity Brittle Lack luster

Properties of Metalloids Properties similar to both metals and nonmetals Example: have luster and is brittle

Alkali Metals (group 1) 1 valence electron (tend to lose it very easily) Most reactive metals They are so reactive they are only found naturally in compounds Can be extracted from compounds using electricity Reacts violently with water to form H 2 (g) and a base Alkali means base (as opposed to acid)

Reactivity of Alkali Metals and Water

Alkaline Earth Metals (group 2) 2 valence e- (tend to lose their 2e- very easily) Active metals Found naturally in compounds Can be extracted from compounds using chemical reactions Reacts quickly with water for form H 2 (g) and a base

Halogens (group17) 7 valence e- (tend to gain 1 e-) Most reactive nonmetals Found as diatomic molecules The only group that contains all 3 phases of matter Can be extracted from compounds using electricity Reacts violently with metals to form halide compounds (like NaCl)

Noble Gases (group 18) 8 valence e- (will not gain or lose) Very stable (not reactive) A few compounds contain the larger noble gases

Transition Elements Group 3-12 Form colored solutions when added to water Can lose different amount of electrons or have multiple oxidation states (ex. Iron can lose 2 or 3 e-)(upper right corner of each box) Range of reactivities, some are quite reactive, others are nonreactive. Some can be found in pure form in nature (Cu, Ag, Au)

Hydrogen 1 valence electron Can lose or gain 1 e- Found as a diatomic molecule

Allotropes These different forms arise because of the different conditions that elements may be found. Examples: Carbon: coal (amorphous mass) diamond (network bonded crystal) graphite (mineral where the carbon atoms are bonded in weakly connected sheet structures) Oxygen: O 2 (diatomic oxygen), O 3 (ozone)

Trends or Patterns in the Periodic Table Ionization Energy: the amount of energy needed to remove a valence electron Electronegativity: the measure of attraction for electrons by the nucleus (how bad does the nucleus want to hold onto its valence electrons Atomic Radius: the size of the atom

Trends or Patterns in the Periodic Table High Electronegativity ____ Ionization Energy What will the radius be, large or small? Small Radius Low Electronegativity ____ Ionization Energy What will the radius be, large or small? Large Radius High Low

Families Periods Columns of elements are called groups or families. Elements in each family have similar but not identical properties. All elements in a family have the same number of valence electrons. Each horizontal row of elements is called a period. The elements in a period are not alike in properties. In fact, the properties change greatly across every given row. The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas.

Trends in Ionic Size: Cations Cations form by losing electrons. Cations are smaller than the atom they came from – not only do they lose electrons, they lose an entire energy level. Metals form cations. Cations of representative elements have the noble gas configuration before them.

Ionic size: Anions Anions form by gaining electrons. Anions are bigger than the atom they came from – have the same energy level, but a greater area the nuclear charge needs to cover Nonmetals form anions. Anions of representative elements have the noble gas configuration after them.

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