For problems involving calculations, show the relevant equation (or formula, and conversion factor(s)), show your work in an organized manner, put the proper units in your calculations / answer, and have the proper number of significant figures in your answer. [60 points]

1. A hypothetical metal requires a minimum frequency of 7.5 * 10 14 Hz to produce the emission of electrons. A photon of light with a wavelength of 125 nm is shined onto the surface of the metal. [15 points]

a. What is the minimum energy needed for the photoelectric effect in this metal ?

b. Does the photoelectric effect occur under this condition ? Justify your answer.

c. If the photoelectric effect occurs, then what is the kinetic energy of the emitted electrons ? If the photoelectric effect does not occur, then what is the range of wavelength of light needed to be shone onto the metal’s surface to observe the photoelectric effect ?

2. Sketch the orbital diagram of ___ and identify the valence electrons and inner shell electrons in the following atoms. [10 points]

a. P

b. Se

 

3. Periodic trends in ionization energy (IE) and atomic size. [15 points]

atom

Size (A)

1st IE (kJ / mole)

Mg

1.60

738

Al

1.25

578

Si

1.17

786

a. rationalize the relative atom size between Mg, Al, and Si.

b. rationalize the relative 1st IE between Mg and Al.

c. rationalize the relative 1st IE between Al and Si.

4. Write the chemical reaction involving ___ as the reactants. [12 points]

a. potassium reacting with chlorine gas

b. add solid nickel oxide into water

c. add solid nickel oxide into an aqueous solution of hydrogen chloride (or hydrochloric acid)

 

5. old topic: organic chemistry [8 points]

a. draw the structural formula of an ether containing a proply group.

b. sketch an isomer of the above compound that is not an ether.