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Shapes of molecules

100

•What is the molecular geometry of a central atom with four bonding domains and two lone pairs around it?

Square planar

200

•What is the bond angle in a linear molecule? Give 2 examples.

180°

CO₂, BeCl₂, N₂, O₂

300

•What is the bond angle in a trigonal planar molecule? Give 2 examples

120°

SO₃, any C=C molecule

400

•Predict the molecular geometry of the following molecules and ions using the VSEPR theory

•A) SO₄^2-

•B) CBr₄

A) Tetrahedral

B) Tetrahedral

500

•Predict the electron-pair geometry of the following molecules and ions using the VSEPR Theory

•A) NH₂^-

B) NO₂^-

A) Tetrahedral B) Trigonal planar

Polarity and Intermolecular forces

100

•Determine whether

•A) NBr3

•B) ClF3

•C) H2O

are polar

They are all polar

200

•List the types of intermolecular forces that exist between molecules (or atoms or ions) in each of the following:

•A) Benzene (C6H6)

•B) NaCl in water

Ans: a) London dispersion ; b) London dispersion, Ion-dipole, +/- hydrogen bonding

300

•Which are the five intermolecular forces? List them from the weakest to the strongest.

Ans: London dispersion < Dipole-induced dipole < Ion-dipole <Dipole-dipole < Hydrogen bonding

400

•Which ONE of the following species is capable of hydrogen bonding?

•A) C2H6

•B) HI

•C) CH3NH2

D) CH3COCH3

Ans: C

500

Is water polar or nonpolar?

Polar

Miscellaneous

100

The chemical formula for water and carbon dioxide...

H₂O

CO₂

200

•What are all the steps used to draw a Lewis structure?

There are 6-7 steps involved

1- count the total number of valence electrons in each atom and add/remove electrons accordingly if there is a charge

2- draw the skeletal structure

3- subtract 2 electrons for each bond

4- complete the octets of as many terminal atoms as possible

5- place the remaining electrons on the central atom

6- use multiple bonds, if necessary, to complete the octets of all the atoms

7- calculate the formal charges of all the atoms. Make sure you have the structure with the smallest formal charge

300

•What is the hybridization around the central atom, S, in SF₆?

Ans: sp3d2

400

•How many orbitals does an sp3d orbital contain?

5

500

•What is the formula unit of the compound made of copper (II) ions and acetate ions?

Ans: Cu(CH3COO)2, alternate answer: Cu(C2H3O2)2