Question

Chapter 6 Homework For math related questions show all of your work and use the correct Answer each question completely. number of significant figures. Anx-ray has a wavelength of 0.13 nm. Calculate the frequency for this wavelength. Calculate the 1. energy (in J) of one photon of this radiation. Calculate the energy in 1 mole of photons. 2. Which of these electron transitions correspond to absorption of energy and which to emission? Which would have the smallest absorption of energy? a. n 2 to n= 3 b. n 5 to n 2 c. n 3 to n1 d. n 3 to n= 4 3. Are the sets of quantum numbers allowed for an electron in an atom? If it is not allowed, explain why. a. n 1,/-0, m 0 b. n 2,-2, m +1 c. n 4,1-3, mi-1 Give the normal electron configuration and the condensed electron configuration for each State how many unpaired electrons it has. 4. atom. Bromine, Z 35 a b. Yttrium, Z = 39 Antimony, Z 51 Write the condensed electron configurations for Ca and Cul* 5. 6. Order the following elements from smallest to largest in size, smallest to largest ionization energy, and smallest to largest electron affinity, based on the trends only. a. Al, Na, S, Mg b. C Sn, Pb, Si c. K, Se, Ca, Br d. O, Se, S, Ne 7. If an atom has a "high first ionization energy" does this mean that it is relatively easy or relatively hard to remove an electron from the atom? A certain atom in the 2d period has an unusually high 3d ionization energy. Name this element. 8.

Answer 1

#1: Given wavelength, $\lambda$ = 0.13 nm * (1m/10⁹ nm) = 1.3*10^-10 m

Frequency,

c/

where c = velocity of light = 3.0*10⁸ m/s

=> $\nu$ = 3.0*10⁸ m.s^-1 / 1.3*10^-10 m

=> $\nu$ = 2.31*10¹⁸ s^-1 or Hz (Answer)

Energy of 1 photon, E = h*$\nu$

=> E = 6.626*10^-34 J.s * 2.31*10¹⁸ s^-1

=> E = 1.53*10^-15 J (Answer)

1 mole photon = 6.023*10²³ photons

=> Energy of 1 mole photon = (1.53*10^-15 J / 1 photon) * 6.023*10²³ photons

= 9.21*10⁸ J (Answer)

#2: When an electron absorbs photon, its energy increases. Hence it moves from lower energy level to higher energy level.

When an electron emits photon, its energy decreases. Hence it moves from higher energy level to lower energy level.

Hence absorption corresponds to: (a): n=2 to n=3, (d): n=3 to n=4

Emission corresponds to: (b): n=5 to n=2, (d): n=3 to n=1