3 chem questions...plz help!

[Ice-cream]

hey guys, i have a few problems which i'm not too sure about...hopefully u guys can help me out!

 

1. A hydrogen atom in its ground state absorbs a photon of wavelength 121.5nm. To which higher energy state will it be excited?

a) n=2 b) n=3 c) n=4 d) n=5

 

(i used E = hc/wavelength to find te energy, which then i made it equal to deltaE = -2.18 x 10^-18 [1/(n final squared) - 1/(n initial squared)] where n initial is 0 because it is in ground state. The answer i got was n = 1.15...which doesn't match any of the choices...can any1 give me some help?)

 

2. Which of the following molecules has a nonlinear structure?

a) XeF2 b) BeCl2 c) O3 d) CO2 e) N20 (central atom is N)

 

(i'm confused about N20 becuase i think theres 2 double bonds; 1 between N-N and 1 between N-O...but i don't think that gives the lowest formal charges...any1 got any other suggestions?)

 

3. A ruby laser produces radiation of wavelength 633nm in pulses of 1.00e-9 s duration. If the laser produces 1.68e-16 J of energy per pulse, how many photons are produced in each pulse?

 

(i used E = hc/wavelength to find the energy of 1 photon. Then i divided the 1.68e-16J by that energy and got 535.468 photons...do u guys think it's right? coz i didn't use the duration time in my calculation so i'm not sure if its right)

 

Thanx

[dan19_83]

Is number two not a single bond for N-N and a triple bond for N-O?