The electron configuration for helium (he) is shown below.
1s2
which diagram shows the correct distribution of electrons in the electron shells of a helium atom?

Explanation :

As we know that the electrons are located around the nucleus in an atom and the arrangement electrons depends upon of their potential energies in the different orbital or shell.

There are some rules of the distribution of electrons in the different shell.

Rule 1 : The maximum number of electrons present in a particular shell is calculated by the formula , where 'n' represents the shell number.

Rule 2 : The maximum capacity to hold the electrons in the outermost shell is 8.

Rule 3 : Once the first shell is full then the next electron is added to the next shell and so on. That means the shell number one i.e, 'K' can hold only two electrons, the shell number two i.e, 'L' can hold eight electrons, and so on.

The given atom is, helium with electronic configuration, . The correct distribution of electrons in the electron shells of a helium atom are shown below.

1.consider the following balanced equation and answer parts a through. show calculations for each part.  

3 ag(s) + 4 hno3(aq) → 3 agno3(aq) + no(g) + 2 h2o(l)  

a. calculate the number of moles of agno3 produced by the reaction of 3 moles of ag with excess hno3. if the number to the left of the compound represents the number of moles of the compound which are present, then 3 moles of ag react with 4 moles hno3 to produce 3 moles agno3 (aq).

so the answer to a would be 3 moles.

b. calculate the number of moles of agno3 produced by the reaction of 108 grams of ag with excess hno3.  

i'm not sure how to plug in the grams of silver into an equation using moles to find how many moles are produced.

c. calculate the number of grams of agno3 produced by the reaction of 108 grams of ag with excess hno3  

d. calculate the number of moles of no produced as a byproduct of the reaction of 108 grams of ag with excess hno3.  

e. calculate the number of grams of no produced as a byproduct starting with 108 grams of ag and excess hno3.  

explanation:

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.