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THE PERIODIC TABLEhttp://www.dayah.com/periodic/Images/periodic table.png
• Mendeleev’s Periodic Table (Figure 6.3)
• Arranged elements into rows and columns
• Elements ordered by atomic mass.
THE PERIODIC TABLE
• Modern periodic tables (Figure 6.5)
• Also arrange elements into rows and columns.
• Elements are ordered by increasing atomic number
PERIODIC LAW
• There are 7 periods (rows) in the periodic table.
• Period 1 = 2 elements• Period 2 = 8 elements• Period 3 = 8 elements• Period 4 = 18 elements• Period 5 =18 elements• Period 6 = 32 elements• Period 7 = 24 elements• Each period = principal energy level.
PERIODIC LAW
• Elements within a Group (column) have similar properties.
• The properties of elements within a period change as you move across a period from left to right.
• PERIODIC LAW STATES: when elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.
Metals, Nonmetals, Metalloids
• Metals• 80% of elements• Good conductors of
heat and electric current
• All are solids at room temperature (EXCEPT: mercury!)
• Ductile (drawn into wires)
• Most are malleable
Metals, Nonmetals, Metalloids
• Nonmetals• Found in the upper
right hand corner of the periodic table
• Most are gases at room temperature (i.e. oxygen and nitrogen)
• Poor conductors of heat and electric current (except carbon)
• Solid nonmetals tend to be brittle
Metals, Nonmetals, Metalloids
• Metalloids• Properties similar
to both metals and nonmetals
• Depending on the conditions a metalloid may behave like a metal or a non metal.
Checkpoint
• Which of these sets of elements have similar physical and chemical properties?
• a. oxygen, nitrogen, carbon, boron• b. strontium, magnesium, calcium, beryllium• c. nitrogen, neon, nickel, niobium• Identify each element as a metal,
metalloid, or nonmetal.• a. gold metal c. sulfur non metal• b. silicon metalloid d.barium metal
Classifying Elements• For helium, label the element symbol, element
name, atomic number and the atomic mass. • Label all groups and periods• Color code (entire box) with key• Metals • Non metals • Metalloids• Gas • Liquid • Solid• Indicate where to find:• Alkali metals, alkaline earth metals, halogens, noble
gases
• *** Put your name and date at the top!
The Representative Elements
• Groups IA through 7A.• The valence electrons (electrons in the highest
occupied energy level)= group number!
Transitional Elements
• Columns 3-12 (or Groups IB-VIIIB)• Transition metals and inner transition metals• Transition metals have e- in d orbitals (main body)• Inner transition metals have e- in f orbitals
(formerly known as rare earth metals)
Practice Problems
• Use figure 6.9 and Figure 6.12 (or the s,p,d,f handout) to write the electron configurations of the following elements.
• A. Carbon• 1s2 2s2 2p2
• B. Strontium• 1s2 2s2 2p63s23p63d104s24p65s2
• C. Vanadium• 1s2 2s2 2p63s23p63d34s2
PERIODIC TRENDS• Atomic Radius• 1/2 the distance
between the nuclei of two atoms of the same element when the atoms are joined.
• Measured in picometers(pm) – there are one trillion
(1012 pm in one meter)
• Decreases because # of protons increases therefore attractive forces are pulling in the e-’s .
• Increases because you are adding more energy levels.
IONS
• Ions-charged atoms due to the gain/loss of electrons
• Anion- ion with a negative (-) charge (nonmetals)
• Cation-ion with a positive (+) charge (metals)
• When compounds form, elements gain or lose e-’s to form ions in order to attain a stable noble gas configuration.
Ionization Energy
• Ionization Energy (IE)• The amount of energy
needed or absorbed to remove an electron from an atom.
• The further away an e- the less IE needed to remove the e-.( but also consider protons and electrons are increasing)
IONIC SIZE
• Anions (-) are larger than cations (+) due to taking e-’s away which reduces the radius.
• Among the anions and cations the trend is the same as atomic radius
• Decreases • Increases
ELECTRONEGATIVITY
• Electronegativity (EN)
• The ability of an atom to attract itself the electrons when in a compound (bonded).
• Electrons shift toward the more EN atom
PERIODIC TREND SUMMARY
PRACTICE
• Atomic Radius--rank the following according to size from smallest to larger.
• Mg, Al, Ca• Al < Mg < Ca• S, Cl, S-2
• Cl < S < S-2
• Fe +2, Fe, Fe +3
• Fe +3 < Fe +2 < Fe
PRACTICE
• Which element in each pair has a higher electronegativity value?
• Cl or F• F• C or N• N• Mg or Ne• Mg• As or Ca• As
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