2-7-1
<h3>Further explanation
</h3>
Electrons can move the shell up or down by releasing energy or absorbing energy
Excited electrons show higher electron transfer to the shell by absorbing energy
So it can be concluded that there are 2 conditions:
Ground state is the state of electrons filling shell with the lowest energy levels.
Excited state is the state of electrons which occupies a higher energy level
The state of excited electrons can be seen from the presence of electrons which do not fill the skin completely but fill the skin afterward
2-7-1
From its 8 electron configuration, filling 3 shells, 2 electrons in the firs shell, 7 electrons in the second shell and 1 electron in the third shell
the electrons in the third shell should fill the electrons in the second shell first according to Aufbau rule (lower energy shells)

The reaction will produce 12.1 g Ag₂S.
<em>Balanced equation</em> = 2Ag + S ⟶ Ag₂S
<em>Mass of Ag₂S</em> = 10.5 g Ag × (1 mol Ag/107.87 g Ag) × (1 mol Ag₂S/2 mol Ag)
× (247.80 g Ag₂S/1 mol Ag₂S) = 12.1 g Ag₂S
increasing the temperature shifts the equilibrium in the direction of the reaction in which heat is absorbed.
Explanation:
The concentration of NO at equilibrium will increase when the reaction takes place at a higher temperature because increasing the temperature shifts the equilibrium in the direction of the reaction in which heat is absorbed.
The reaction is an endothermic reaction.
N₂ + O₂ + heat ⇄ 2NO
According to Le Chatelier's principle, "if any of the conditions of a system in equilibrium is changed the system will adjust itself in order to annul the effect of the change".
- In an endothermic reaction, heat is usually absorbed.
- We see that in the backward reaction, heat is absorbed.
- If the temperature of this reaction is increased, the backward reaction is favored more.
- Since the reactants are combining better, more products NO results.
learn more:
Thermodynamics of reactions brainly.com/question/10567109
#learnwithBrainly
C) Nucleus...... Hope it helps, Have a nice day :)