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# Physics Homework Help

1. An electron with amass of 9.11*10 -31 kg has a velocity of 4.3*10 6m/s in the innermost orbit of a hydrongen atom. What is the de Broglie wavelength of the electron?

7. An electron wave making a standing wave in a hydrogen atom has a wavelength of 8.33*10 -11m. If the mass of the electron is 9.11*10 -31kg, What is the velocity of the velocity of the electron according to the de Broglie equation?

8. Using any reference you wish, write the complete electron configurations for (a) nitrogen, (b) phosphorus, and (c) chlirine.

12. Identify the number of protons, neutrons, and electrons in the following isotopes:
(a) 14/4 N
(b) 7/3 Li
(c) 35/17 C
(d) 48/20 Ca
(e) 63/29 Cu
(f) 230/92 U

13. identify the period and the family in the periodic table foe the following elements:

(a) Xeron
(b) Potassium
(c) Chromium
(d) Argon
(e) Bromine
(f) Barium

17. Use the periodic table to identify if the following are metals, nonmetels, or semiconductors:

(a) Kyrpton
(b) Cesium
(c) Silicon
(d) Sulfur
(e) Molybdenum
(f) Plutonium

#### Solution Preview

1. The de Broglie wavelength is equal to:
lambda = (h/(m*v))*sqrt(1 - v^2/c^2)

Substituting the values, we have:
lambda = (6.626x10^-34)/(9.11x10^-31 * 4.3x10^6) * sqrt(1 - (4.3x10^6)^2 / (3x10^8)^2)
lambda = 1.69x10^-10 m

7. Using de Broglie equation, we can solve for velocity:
lambda = (h/(m*v))*sqrt(1 - v^2/c^2)
8.33x10^-11 ...

#### Solution Summary

This posting contains the solution to the given problems.

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