Chapter 6

Which statement is true? (use Periodic Table) A. Elements in the same column ↕ has same # of outer shell electrons B. Elements in the same row ↔ has same # of outer shell electrons

Arrangement: Increasing atomic number Interesting observations:  Discrepancies in Mendeleev’s table disappeared (Te before I)

Inner Transition Metals

Hydrogen  Most common element in universe  charge: 1+ or 1- Alkali Metal (Group 1, except H)  Highly reactive with water  Soft and can be easily cut  Charge:1+ Alkaline-earth metal (Group 2)  Less reactive than alkali metals  Harder than alkali metals  Charge: 2+

Transition metals (d-block)  No identical valence electrons (charge varies)  Less reactive than group 1 & 2 Inner Transition metals (f-block)  Nuclei are unstable – radioactive  (charge varies)

Halogens (Group 17)  Most reactive group of non-metals  Likes to react with alkalis to produce salts  charge :1-

Noble gases (Group 18)  Low chemical reactivity b/c very stable  Outermost energy level is full  Does not form ions Glow brightly when an electric discharge is passed through them

ANION: (-) ions Halogens: Cl gains 1 e- 1s 2 2s 2 2p 6 3s 2 3p 5 1s 2 2s 2 2p 6 3s 2 3p 6 (Cl)(Cl-) Ar

As you look down a column, the outermost principle energy level __________________. (but the number of valence e - ‘s stays the same) As more and more levels become filled with electrons, the nucleus becomes ______________ effective at attracting the outer electron(s). This is known as the “shielding effect.” (As you look down a column, even though the nucleus theoretically is stronger since it has more protons, it is NOT effective at holding onto the outer electrons.) Which energy level has NO shielding? ____________ Which atom holds onto the outer electron tighter, K or Rb? Why? ____ has one more filled level than ____ and therefore is _____ effective at holding onto the outermost (valence) electron. INCREASES LESS 1 Rb K

Is the shielding effect an issue with a row?_____ Row, Period, Series Val. n=2 n=2 n=2 n=2 n=2 n=2 n=2 n=2 energy level filled ____ ____ ____ ___ ___ ____ ___ ____ Levels The energy level is not changing. What is changing? Is the nucleus getting stronger?_________. Is it effective?________ In a row, ___________ ___________(and not shielding) determines the trend YES NUCLEAR CHARGE NO

Distance from nucleus to outer electrons Bond radius = ½ distance between nuclei of adjacent atoms.

Metals tend to _________ electrons and become ____________ions. (gain or lose) positive or negative) ** (metal ions are ___________than metal atoms) (smaller or larger) Non- metals tend to _______ electrons and become __________ ions. (gain or lose) (positive or negative) ** (non-metal ions are ______________than non-metal atoms) (smaller or larger) lose positive smaller gainnegative larger

Energy required to remove an electron from an atom or ion (form (+) ion).

Down a Group: Decreases (easier to remove an electron) Reason: 1. more energy levels (outermost electrons are farther from nucleus) 2. more shielding (less attraction btw p+ & val. e-) Across a Period: Increases (harder to remove an electron) Reason: 1. more nuclear charge, p+ ↑ 2. radius decreases  Electron-shielding remains the same

Lower down in a column the atoms are larger / smaller and have more attractiveness / shielding so it is easier to remove an e - from the outer shell. It is harder/easier to remove an electron from a small atom with no shielding. It gets harder/easier to remove that electron as you move to the right as it approaches a perfect octet. Which column would be very difficult to go in and remove and electron from? Noble gases So the column with the highest Ionization Energy = Group # 18, Noble gases Ionization Energy pg-10 Circle the correction answer & answer the last 2 questions

Down a Group: Decreases (less attraction towards bonding e-) Reason: 1. more energy levels 2. more shielding Across a Period: Increases (more attraction towards bonding e-) Reason: 1. radius decreases (val. e- closer to nucleus) 2. nuclear charge increases, p+ ↑

Electronegativity of Fluorine is >, =, < the electronegativity of hydrogen Electronegativity of Chlorine is >, =, < the electronegativity of Chlorine In water, does Hydrogen or Oxygen pull harder on the shared pair of electrons? ____________ Which column does NOT bond with any element (because it has a perfect octet)? ____________________ (No electronegativity values are assigned) NOBLE GASES

Atomic mass: mass in grams = 1 mole of that element Example: 12 g C = 1 mol C Molecular mass: mass of a molecule = 1 mole of that molecule Example: 32 g O 2 = 1 mol O 2 Diatomic Elements (BrINClHOF): Br 2 I 2 N 2 Cl 2 H 2 O 2 F 2 Elements found in pairs