Do Now Announcements Work on Do Now take

Do Now & Announcements �Work on Do Now & take out notes from yesterday �I will collect your labs tomorrow �Unit 4 Test THURS 10/9 �Unit 3 Quest Corrections due FRI 10/10

K 1 s 22 s 2 [He]2 s 2 [Ar]4 s 1

Valence Electrons �The electrons in the outermost shell or highest energy level �Total number of electrons in the highest energy s and p orbitals!

K Te 1 s 22 s 2 [He]2 s 2 [Ar]4 s 1 1 s 22 p 63 s 23 p 64 s 23 d 104 p 65 s 24 d 105 [Kr]5 s 24 d 105 p 4

Electronic Battleship

Noble Gases: Group 18 �Have octet=full valence (outermost) shell ◦ All elements want to be a noble gas (so freaking bad). In other words, all elements want to have a full valence shell ◦ Remember: “ 8 IS GREAT!” ◦ Exception: helium: it only has 2 valence electrons

Obtaining a Noble Gas Electron Configuration �Elements can lose or gain electrons in order to get a noble gas’ electron configuration ◦ Depending on the element, sometimes it is “easier to lose electron(s)”, and sometimes it is “easier to gain electron(s)”

Getting a Full Outer Shell Lithium (Li) 1 s 22 s 3 P + 4 N REMOVE 1 ELECTRON 3 P + 4 N 1 ADD 7 ELECTRONS 3 P + 4 N 1 s 2 Which way is easier? 1 s 22 p 6

Getting a Full Outer Shell Fluorine (F) 1 s 22 p 5 9 P + 10 N ADD 1 ELECTRON REMOVE 7 ELECTRONS 9 P + 10 N 1 s 22 s 22 p Which way is easier? 6

5 s 25 p 6

Isoelectronic Species �Elements/ions that have the same number of electrons p=8 n=8 e = 10 p=9 n=9 e = 10 p = 10 n = 10 e = 10 p = 11 n = 11 e = 10 p = 12 n = 12 e = 10 8+ - - 9+ - - 10+ - - 11+ - - 12+ - - Oxygen ion O 21 s 22 p 6 Fluorine ion F 11 s 22 p 6 Neon atom Ne 2 1 s 2 s 22 p 6 Sodium ion Na 1+ 1 s 22 p 6 Magnesium ion Mg 2+ 1 s 22 p 6 - -