Ch. 5 PERIODIC TABLE - Periodic Law Groups Periods

Mendeleev 1st dude to arrange the elements in order of increasing mass so the similar elements were in the same column (remember this!!!!!)

Periodic Law = elements arranged by increasing atomic number Modern Periodic Law Periodic Law = elements arranged by increasing atomic number

Groups are the vertical columns in the periodic table (1-18)

Groups Elements in Same Group = Act the same!!!!! Just like Mendeleev predicted, NOT BAD FOR AN OLD SCHOOL GUY

Groups Nitrogen (N) will act/behave more like Phosphorus (P) because they are in the same GROUP. Group 15

QUESTION Which element would act most like Fluorine? Sulfur Carbon Chlorine Hydrogen

Periods are the horizontal rows of the periodic table (1-7)

Sentences are read HORIZONTALLY, and end with a PERIOD. Periods vs Groups Sentences are read HORIZONTALLY, and end with a PERIOD.

Question Group Period Aluminum Calcium

Valence Electrons Valence Electrons - are the electrons in the OUTERMOST (highest) energy level

Octet Rule Every atom wants 8 valence electrons, so they will gain or lose them to get that 8 8 = Stable

Group 18, the noble gases have 8 valence electrons Octet Rule Group 18, the noble gases have 8 valence electrons VERY VERY STABLE, THEY DON’T REACT

Octet Rule

Phosphorus (neutral) Atomic # = 15 Protons = 15 Electrons = 15 Mass # - Atomic # = # Neutrons 31 - 15 = 16 Neutrons P = 16 N = 15 Valence Electrons = 5

Phosphorous wants 8 electrons in it outer energy level to be stable Phosphorous wants 8 electrons in it outer energy level to be stable. (8=stable)

Gains 3 Electrons to get that magic number 8 Phosphorous ION Gains 3 Electrons to get that magic number 8 P = 16 N = 15

Phosphorous Ion P-3

Magnesium (neutral) Atomic # = 12 Protons = 12 Electrons = 12 Mass # - Atomic # = # Neutrons 24 - 12 = 12 Neutrons P = 12 N = 12

Easier for it to lose 2 electrons to have its lower energy level full Magnesium Ion Easier for it to lose 2 electrons to have its lower energy level full P = 12 N = 12

Magnesium Ion Mg +2

Charges of the groups Group 1 = +1 Group 2 = +2 Group 13 = +3 Group 14 = +/- 4 Group 15 = -3 Group 16 = -2 Group 17 = -1 Group 18 = 0 (stable)

Color ANOTHER periodic table Read through pages 140-145 and color the 8 different categories of elements from the book on your small periodic table

Electro negativity Electronegativity – ability of an element to attract electrons (-) to itself

Electro Negativity Trend in periodic table: Increases from LEFT – RIGHT Increases from BOTTOM - TOP

INCREASING ELECTRONEGATIVITY

Which element has a greater electronegative value? Be Na O Ca

TAKS TOPIC REMEMBER THIS FLUORINE – most electronegative element (best looking element, everything is attracted to FLUROINE)

Atomic Radius – how big an atom is in size

Atomic Radius Atomic Radius trend: -INCREASES from RIGHT – LEFT - INCREASES from TOP - BOTTOM

INCREASING ATOMIC RADIUS

Question Which element has the biggest atomic radii? Sr B F Be