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Periodic Table The Basics
Chemistry
Mrs. Sousa & Mr. Pickin
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Introduction
This presentation will give you all the information you need to know about the basic organization of the periodic table
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Origin
The periodic table was first devised by Dmitiri Mendeleev in Russia in 1869
Based on the “Periodic Law” which states that the properties of the elements repeat periodically
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Basics Elements listed by increasing atomic number
(Unique for each element) (thus properties)
Atomic number is the number of protons contained in the nucleus of an atom of an element
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Major Divisions in Table Metals (<4 valence electrons)
form + ions (cations). Ionic bonds Non-metals (>4 valence electrons)
form - ions (anions). Covalent bonds Metalloids (semi-metals) Separated by zig-zag line Image
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Periods
Horizontal (across) rows are called periods. Properties of elements change across the period.
7 periods (maximum)
Period number is the number of energy levels each element contains in that row(quantum # n value as well)
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Groups/FamiliesEither term acceptable
Vertical columns 18 families
Numbered from left to right
Members of the same family have very similar chemical and physical properties. Atoms increase in size as you get lower in a group.
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Representative Families. Representative families are 1,2,13,
14,15,16,17,18 Ones place is the number of valence electrons In other words- for 13-18 put your finger over the #1! Ex. Family 16 has 6 valence electrons Valence electrons are those in the outer energy level –
they are used for bonding and come from the s & p orbital space
Noble Gases (group #18) all have 8 valence electrons. Exception to the octet rule: He (helium) has 2 valence
electrons
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Common Names 1-Alkali metals (most active metals) 2-Alkaline earth metals 16-Chalcogens 17-Halogens (most active non-metals) 18- Noble gases (not reactive) 3-12 Transition metals (1 or 2 valence
electrons)
Lanthanide series (AN 57-71)
Actinide series (AN 89-103)
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Regions of the Periodic Regions of the Periodic TableTable
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Group 1: Alkali Group 1: Alkali MetalsMetalsGroup 1: Alkali Group 1: Alkali MetalsMetals
Cutting sodium metalCutting sodium metal
Reaction of potassium + H2O
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MagnesiumMagnesium
Magnesium Magnesium oxideoxide
Group 2: Alkaline Earth MetalsGroup 2: Alkaline Earth Metals
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Group 17: The Group 17: The Halogens (salt Halogens (salt makers) makers) F, Cl, Br, I, AtF, Cl, Br, I, At
Group 17: The Group 17: The Halogens (salt Halogens (salt makers) makers) F, Cl, Br, I, AtF, Cl, Br, I, At
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Group 18: Group 18: The Noble (Inert) The Noble (Inert) GasesGases
He, Ne, Ar, Kr, Xe, RnHe, Ne, Ar, Kr, Xe, Rn
Group 18: Group 18: The Noble (Inert) The Noble (Inert) GasesGases
He, Ne, Ar, Kr, Xe, RnHe, Ne, Ar, Kr, Xe, Rn
Lighter than air balloons
“Neon” signs Very Unreactive
because they have full electron levels
XeOFXeOF44XeOFXeOF44
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Transition Metals (elements) Families 3-12 Lanthanide series click Actinide series Multivalent – can have 1, 2, 3 valence
electrons – depending on what other atoms they are bonding with.
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Transition Transition ElementsElementsTransition Transition ElementsElements
Lanthanides and actinidesLanthanides and actinides
Iron in air gives Iron in air gives iron(III) oxideiron(III) oxide
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s, p, d, f blocks
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Atomic Radius (size) • The trend is that:
•Atoms get smaller going across a period (Noble gases are the exception)
•Atoms get larger going down a family
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Atomic Radius (cont.)
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Atomic Radius (cont)
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Ionization Energy (IE)
The amount of energy necessary to remove one or more electrons from an atom in its gaseous state
Generally: Metals have low IE Non-metals have high IE
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Ionization Energy (IE)
IE increases across a period IE decreases down a family
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Electronegativity (EN) The tendency of an atom to attract electrons (affinity for
electrons)
An atom's electronegativity is affected by both the positive charge in the nucleus and the distance that its valence electrons reside from the charged nucleus.
The higher the associated electronegativity number, the more an element or compound attracts electrons towards it.
Range of EN’s for the elements is 0.7 (Fr) to 4.0 (F) Trend:
EN increases across a period and decreases
down a family
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Electronegativity (EN) Trend
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Electronegativity (cont.)
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Electron Affinity The energy released when an electron is
added to a neutral atom. (exothermic process) for the first added electron the process is exothermic