Identity: Electron Configurations

1. Identify the elements with the following electron configurations:
(a) (i) [Ne]3s1 (ii)[Ne]3s2 (iii) [He]2s22p5 (iv)[Ne]2s22p5
(b) Indicate the period and group of the periodic table that the elements belong.

2. Name and write the electron configuration of the element in period 4 and group 16 (VIA) of the following periodic table.

Periodic Table Subshells

3. Using the periodic table of figure 9.16, write the electron configuration of Iodine and indicate its valence-shell configuration.

Grouping/Interaction: Polar Molecules.

DiChloroethylene Dipole Moment

(1) A diatomic molecule is made up of the nonradioactive atoms X and Y.
(a) Identify X and Y if the electronegativities of X and Y are respectively, the lowerbound and upperbound of the range containing the electronegativities of all nonradioactive elements.
(b) Is this diatomic molecule polar or nonpolar?

(2) Given that the diatomic molecule HF (hydrogen fluoride) has a bond length of 0.92Å; 1.96 electronegativity difference and dipole moment of 1.82 Debyes:

(a) Calculate the effective charges on the H and F atoms of the HF molecule in units of the electronic charge, e.
(b) Consider this sequence of Hydrogen Halides: HF, HCl, HBr, HI. As we proceed from HF to HI the bond lengths are increasing while the dipole moments are decreasing. Why?

(3) The three isomers of Dichloroethylene are as follows:


An experiment shows that a pure sample of one of these isomers has a dipole moment of zero. Determine which of the isomers in figure 9.37 was measured.

Grouping/Interaction: Electron Domain Geometry And Molecular Geometry Of Non-ABn Molecules.

Lewis Structure Acetic Acid

The above diagram is the Lewis structure of acetic acid. Predict the molecular geometry of acetic acid from its Lewis structure and the bond angles associated with its geometry.

Grouping/Interaction: Electron Geometry And Molecular Geometry Of ABn Molecules.

Molecular Geometry CCl<sub>4</sub>

The following problems refer to ABn molecules:
(1) How meaningful is the molecular shape of the molecule with n = 1?
(2) What is the value of n for the following molecules?:
(a) CO2 (b) SO3 (c) CCl4
(3) Determine the Lewis structure for the following molecules:
(a) CO2 (b) H2O (c) BF3 (d) XeF4
(e) CCl4 (f) NH3 (g) PCl5 (h) SF6
(4) Use the Valence-Shell Electron-Pair Reduction (VSEPR) model to predict the molecular shapes and bond angles of the molecules indicated in problems 3a, 3c, 3e, 3g and 3h.
(5) Predict the molecular geometries of the molecules of 3b, 3d and 3f, from the electron-domain geometries of problem (4). Will the bond angles of these molecules be greater or smaller than the bond angles indicated in the electron-domain geometries from which their molecular geometries were derived?

Identity: Determining Empirical Formula

Determine the empirical formula of an organic compound X, which contains only C (carbon), H (hydrogen) and Cl (chlorine). Given that a complete combustion of 1.50 g sample of X in air formed 3.52 g of CO2 (carbon dioxide) and that in a separate experiment the chlorine in a 1.00 g sample of X was converted to 1.27 g of AgCl (silver chloride).

Identity: Molecular Formula, Empirical Formula And Structural Formula.

(1) How are the empirical formula, molecular formula and structural formula of a compound different from one another?

(2) Determine the molecular and empirical formulas of the following:
(a)benzene (b) silicon tetrachloride (c) diborane (d) glucose

(3) What is the structural formula for the following molecular model?:

Structural Formula Methanol

Containership: The Law Of Constant Composition.

Sample A of ascorbic acid (vitamin C) is synthesized in the laboratory.
Sample B of ascorbic acid is isolated from citrus fruits. Sample A contains
1.50 g of carbon and 2.00 g of oxygen. How many grams of oxygen are in sample B, if sample B contains 6.35 g of carbon?

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