1. Silicon has the electronic configuration 1s2 2s2 2p6 3s2 3p2.  Discuss how you can determine that 1s2 2s2 2p6 3s2 3p2 is the electronic configuration for silicon. 2. What is a reason potassium tends to lose one electron to form a +1 ion K+1?  What is the reason chlorine tends to add one electron to form the -1 ion Cl-1 ?  Hint:  They are the same reason. 3. In the abbreviated electronic figure for phosphorus [Ar] 3s2 3p3 how do you know what are the core electrons?   4. A student got a problem wrong.  They were asked,  “How many grams of MgCl2 (molar mass = 95.21 g/mol) are needed to make 3.16 L of a 0.500 M MgCl2 solution?”  The correct answer is 150. but the student got 1.58.  What mistake did the student make? 5. To solve the following problem what is the reason you must subtract the vapor pressure of water, 24 torr, from the total pressure, 747 torr in order to solve the problem? “A 500.0-mL sample of H2 gas is collected over water at 298 K and 747 torr.  What volume would the dry H2 gas occupy at STP?  (Given: the vapor pressure of water at 298K is 24 torr).” By the way, the answer is .436 liters. NOTE:  I am not asking you to solve this problem.  I am asking the reason for subtracting the vapor pressure.  If you simply solve the problem, you will get no points.

1. Silicon has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p².  Discuss how you can determine that 1s² 2s² 2p⁶ 3s² 3p² is the electronic configuration for silicon.

2. What is a reason potassium tends to lose one electron to form a +1 ion K⁺¹?  What is the reason chlorine tends to add one electron to form the -1 ion Cl^-1 ?  Hint:  They are the same reason.

3. In the abbreviated electronic figure for phosphorus [Ar] 3s² 3p³ how do you know what are the core electrons?  

4. A student got a problem wrong.  They were asked,  “How many grams of MgCl₂ (molar mass = 95.21 g/mol) are needed to make 3.16 L of a 0.500 M MgCl₂ solution?”  The correct answer is 150. but the student got 1.58.  What mistake did the student make?

5.

To solve the following problem what is the reason you must subtract the vapor pressure of water, 24 torr, from the total pressure, 747 torr in order to solve the problem?

“A 500.0-mL sample of H₂ gas is collected over water at 298 K and 747 torr.  What volume would the dry H₂ gas occupy at STP?  (Given: the vapor pressure of water at 298K is 24 torr).”

By the way, the answer is .436 liters.

NOTE:  I am not asking you to solve this problem.  I am asking the reason for subtracting the vapor pressure.  If you simply solve the problem, you will get no points.