Helium has two valence electrons, and these electrons sre located in the 1s subshell. without using the periodic table, in which group and period is helium located? a .group 8a, period 1 b. group 6a, period 3 c. group 3a, period 3 d. group 3b, period 6

The answer s... A: Group 8A, Period 1

The way I found this doesn't have much thought or explanation--I just remember that helium and hydrogen are in period 1. The only answer choice with "period 1" is A.

Option (A) is the correct answer.

Explanation:

Atomic number of helium is 2 and its electronic configuration is . As here n = 1 this means that helium element belongs to period 1.

Since, helium atom has completely filled s-shell this means that it is unreactive in nature as it neither needs to lose or gain an electron in order to attain stability.

And, all the unreactive elements in the periodic table belongs to group 8A. That is why, helium also belongs to group 8A and period 1.

Thus, we can conclude that helium is located in Group 8A, Period 1 .

introduction of a drug directly into the respiratory tract is a form of inhalation administration.

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: