LT2: Periodic Table Basics

How is the periodic table arranged? Mendeleev first arranged it by average atomic mass. Mosley then arranged it by increasing ATOMIC NUMBER

Columns= Families or Groups Rows= Periods The transition metals are not considered a “family”

Blue= METALS Yellow= NONMETALS Pink= Semimetals (Metalloids)

Transition Metals G8: Noble Gases G7: Halogens G3: Boron Group G1: Alkali Metals G4:Carbon Group G5:Nitrogen G6: Oxygen G2: Alkaline Earth Metals Transition Metals Inner Transition Metals

Compare electron configurations down a group and across a period Compare electron configurations down a group and across a period. What do they have in common? Group Ca Sr Common: Period Ga

Don’t forget the blocks on the periodic table!

FLIP TO THE BACK OF YOUR PAGE FOR NOTES ON… LABEL YOUR PAPER LIKE THIS: PROPERTIES OF METALS PROPERTIES OF NONMETALS PROPERTIES OF SEMIMETALS (METALLOIDS) Additional Information about Specific Groups:

METALS PROPERTIES OF METALS DUCTILE MALLEABLE LUSTEROUS SOLIDS AT ROOM TEMP SMOOTH CONDUCTORS

PROPERTIES OF NONMETALS NOT CONDUCTORS NOT MALLEABLE NOT DUCTILE NOT LUSTEROUS--DULL BRITTLE SOLIDS OR GASES AT ROOM TEMPERATURE

PROPERTIE S OF SEMIMETALS (METALLOIDS)

ADDITIONAL INFORMATION ABOUT EACH GROUP…

ALKALI METALS GROUP 1 VALENCE ELECTRONS—1 MOST REACTIVE METALS ON THE TABLE

ALKALINE EARTH METALS GROUP 2 2 VALENCE ELECTRONS 2ND MOST REACTIVE METAL GROUP ON THE TABLE

HALOGENS GROUP 7 7 VALENCE ELECTRONS MOST REACTIVE GROUP ON THE TABLE

NOBLE (INERT) GASES GROUP 8 8 VALENCE ELECTRONS DO NOT REACT (HARDLY EVER)

VALENCE NUMBER FOR EACH GROUP

LT3: Periodic Trends Atomic Radius- half the distance between 2 adjacent nuclei. Illustration

Reasoning Period- As you move across a period valence electrons occupy the SAME ENERGY LEVEL. However, the pull from the nucleus increases as more protons are added pulling the electrons in DECREASING the size of the atom. Group- As you move down a group the valence ENERGY LEVEL INCREASES which causes the atom to get larger.

Ionic Size- when atoms gain or lose electrons they become IONS CATION ANION FROM A LOSS OF ELECTRONS= POSITIVE CHARGE SMALLER THAN NEUTRAL ATOM LOSE ENERGY LEVELS DECREASE IN ELECTROSTATIC REPULSION FROM A GAIN OF ELECTRONS= NEGATIVE CHARGE LARGER THAN NEUTRAL ATOM INCREASES THE ELECTROSTATIC REPULSION

IONIZATION ENERGY- ENERGY NEEDED TO REMOVE AN ELECTRON FROM AN ATOM Illustration

Reasoning Periods- As you move across the period, the atoms are getting smaller and closer to having a full valence shell (8 electrons) so it is HARDER or requires HIGHER Ionization Energy to remove electrons because atoms tend to keep their electrons. Groups- As you move down a group, the atoms are getting larger so it is EASIER or requires LOWER Ionization Energy to steal electrons because the attraction between p+ and e- is decreasing.

Electronegativity- ability to attract electrons in a bond. Most Electronegative Illustration Least Electronegative

Reasoning Period- Across a period the elements are closer to having a full octet (8 valence electrons) so they attract electrons more to reach the full valence shell. (excluding the Noble Gases) Group- Going down a group there is less attraction from inside the nucleus to outside on the valence shell due to a larger size which decreases the electronegativity down a group.

Practice Which of the following is the smallest? Highest Ionization energy? Cl, Se, Br Which of the following is the largest? Highest Ionization energy? P, S, Se Which of the following is the largest atom? Smallest Ionization energy? Sc, Y, La Which of the following is the smallest? Highest electronegativity? V, Cr, W

Practice Which of the following is the largest? Te 2-, I1-, Xe Which of the following is the smallest? Li, Li1+, Na Put these in order from largest to smallest electronegativity. B, Na, K, Al

Successive Ionization Energy- What do you think this term means and why does it change like this?

Energy needed to remove successive electrons from an atom Energy needed to remove successive electrons from an atom. (the first, the second, the third, etc.) It changes based on valence electron number.