Chem exam 3& 4

Use VSEPR Theory to predict the molecular geometry around the central atom in each of the following molecules. Which of the following molecular geometries are correct? 1. NO2-, bent 2. HF, tetrahedral 3. SF4, seesaw

1 and 3

Which of the following molecules are polar? 1. CHCl3 2. O2 3. HBr

1 and 3

Which of the following molecules are polar? 1. BCl3 2. H2S 3. BrF5

2 and 3

How many sigma (σ) bonds and pi (π) bonds are in carbon dioxide?

2 sigma and 2 pi

How many equivalent Lewis structures are needed to represent the bonding in the nitrate ion, NO3- ?

3

Use VSEPR Theory to predict the molecular geometry around the central atom in each of the following molecules. Which of the following molecular geometries are correct? 1. PF5, T-shaped 2. SF6, trigonal bipyramidal 3. XeF4, square planar

3

What is the B-F bond order in BF3?

1

How many equivalent Lewis structures are needed to describe the bonding in CO3 2- The average C-O bond order is ____.

3, 4/3

Which combination of atoms is most likely to produce a compound with covalent bonds? A，Li and I B，Al and S C，K and Br D，Na and F E，S and Cl

E

Rank F, Cl, and Br in order of increasing first ionization energy.

Br<Cl<F

Which bond is most polar?（ great differ electronegativity） N?S C?O F?F N?C

CO

Which one of the following atoms is paramagnetic in the ground electronic state? A, Cd B, He C, Ar D, Bi E, Mg

D

Which element has the ground state electron configuration 1s22s22p63s23p3?

P

Which of the following atoms is diamagnetic in the ground electronic state? I Ge Sr Mn S

Sr

What is the molecular geometry around the central atom of NH3?

Trigonal pyramid

Place the following ions in order from smallest to largest ionic radii: Se2-, Sr2+, Y3+, and Br-

Y3+ < Sr2+ < Br- < Se2-

What is the ground state electron configuration for Co2+?

[Ar] 3d7

What is the ground state electron configuration for Na?

[Ne] 3s1

In general, atomic radii

increase down a group and decrease across a period

Electronegativity is a measure of

the ability of an atom in a molecule to attract electrons to itself