Announcements Clicker #1 Be respectful – no electronics please! Announcements Clicker #1 What is the electron configuration for hydrogen? A) 1s0 B) 1s1 C) 1s2 D) 1s2s1 E) 1s22s2 Pre/post lecture assignments due as usual Tuesdays & Thursdays at 8:00 am Textbook homework due tomorrow Lab on Monday

Atomic Radius (Size) Decreases across a row (period) – outer electrons in the same energy level Lithium Fluorine DECREASES! More protons in each element as you move across the row. More protons will create a stronger positive force, thus attracting the electrons more strongly, pulling them in and shrinking the size.

Electron Configuration: The Finer Points Name that element, in an excited state! 1s22s13s1 Number of unpaired electrons in this excited state? Number of unpaired electrons in ground state? Beryllium 2

Atomic Radius (Size) Increases down a group Hydrogen Francium Orbitals are getting larger and electrons fill further and further from the nucleus at higher energy levels

General Trend (Atomic Size/Radius)

Clicker #2 Which of the following elements has the largest atomic radius? A) Ca B) Al C) N D) Sr E) F

Discussion #1 Of the atoms in the previous example for which would it be easiest to remove an outer electron? 1) H (has fewest electrons) 2) He (is the smallest atom) 3) Li (is the largest atom) 4) Be (has the greatest number of electrons 5) All the same

Ionization Energy Decreases down a group Hydrogen Francium Orbitals are getting larger and electrons fill further and further from the nucleus at higher energy levels. Electrons are not as tightly bound by the nucleus at higher energy levels so it takes less energy to remove an outer electron.

Ionization Energy Increases across a row (period) – outer electrons in the same energy level Lithium Fluorine INCREASES! More protons in each element as you move across the row. More protons will create a stronger positive force, thus attracting the electrons more strongly and pulling them in closer to the nucleus, requiring MORE energy to remove an outer electron.

General Trend (Ionization Energy)

Clicker #3 Which of the following elements has the largest ionization energy? A) P B) Al C) Cl D) Ba E) K

Discussion #2 How many electrons would a neutral atom of lithium have to lose or gain to end up with the same number of electrons as helium? 1) Gain 1 electron 2) Lose 1 electron 3) Gain 2 electrons 4) Lose 2 electrons 5) No change needed (already has the same number of electrons)

Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure Molecular Properties

Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure Molecular Properties

Bond (Intramolecular) Force that holds groups of two or more atoms together and makes them function as a unit. Bond is more stable than the two separated atoms (lower energy state).

Electronegativity

Ionic Bonding

Ionic Bonding

Covalent Bonding

Covalent Bonding

Polar Covalent Bonding

Polar Covalent Bonding

Clicker #4 Rank the following bonds from least polar to most polar: Si-Cl P-Cl Mg-Cl S-Cl A) S-Cl, P-Cl, Mg-Cl, Si-Cl B) P-Cl, S-Cl, Si-Cl, Mg-Cl C) Mg-Cl, Si-Cl, P-Cl, S-Cl D) Mg-Cl, S-Cl, P-Cl, Si-Cl E) S-Cl, P-Cl, Si-Cl, Mg-Cl