3 years ago

Which metal is more reactive calcium or cobalt

1 answer:

mihalych1998 [28]3 years ago

4 0

Calcium would be more reactive because it is closer to francium on the periodic table, francium is the MOST reactive element.

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Use the periodic table entry below to answer the following question. What is the atomic mass of the element cobalt (Co)?

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What is the wavelength of radiation emitted when an electron goes from the n = 7 to the n = 4 level of the Bohr hydrogen atom? G

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Answer:

the wavelength of radiation emitted is $\mathbf{\lambda= 2169.62 \ nm}$

Explanation:

The energy of the Bohr's hydrogen atom can be expressed with the formula:

$\mathtt{E_n =- \dfrac{13.6\ ev}{n^2}}$

For n = 7:

$\mathtt{E_7 =- \dfrac{13.6\ ev}{7^2}}$

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For n = 4

$\mathtt{E_4=- \dfrac{13.6\ ev}{4^2}}$

$\mathtt{E_4 =- 0.85\ eV}$

The electron goes from the n = 7 to the n = 4, then :

$\mathtt{E_7-E_4 = (-0.27755 - (-0.85) ) \ eV}$

$\mathtt{= 0.57245\ eV}$

Wavelength of the radiation emitted:

$\mathtt{\lambda= \dfrac{hc}{0.57245 \ eV}}$

where;

hc = 1242 eV.nm

$\mathtt{\lambda= \dfrac{1242 \ eV.nm }{0.57245 \ eV}}$

$\mathbf{\lambda= 2169.62 \ nm}$

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What kind of thermochemical equation is represented below?

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