Answer:
Part A:
Charge is 
Configuration is 
Part B:
Charge is 
Configuration is 
Part C:
Charge is 
Configuration is 
Explanation:
Monatomic ions:
These ions consist of only one atom. If they have more than one atom then they are poly atomic ions.
Examples of Mono Atomic ions: 
Part A:
For P:
Phosphorous (P) has 15 electrons so it require 3 more electrons to stabilize itself.
Charge is 
Full ground-state electron configuration of the mono atomic ion:

Part B:
For Mg:
Magnesium (Mg) has 12 electrons so it requires 2 electrons to lose to achieve stable configuration.
Charge is 
Full ground-state electron configuration of the mono atomic ion:

Part C:
For Se:
Selenium (Se) has 34 electrons and requires two electrons to be stable.
Charge is 
Full ground-state electron configuration of the mono atomic ion:

Answer:
Relative motion of source and observer.
Explanation:
Doppler Effect : It is the change in the observed frequency of the wave due to<em><u> relative motion of the source and object </u></em>.
0.086mole
Explanation:
The problem is very simple. It involves conversion from mass to number of moles of NaCl
What is mole?
A mole is a unit of measuring chemical substances. It is the amount that contains the avogadro's number of particles.
How is it related and can be converted from mass;
Number of moles of a substance = 
Since we know the mass, we can find the molar mass and put into this equation;
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Number of moles of NaCl =
0.086mole
learn more:
Number of moles brainly.com/question/1841136
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