Question

1. define valence electrons and explain why they are important.
2. cosmic rays are high - energy radiation from outer space. what is the frequency of a cosmic ray that has a wavelength of 2.67×10^(-13) m when it reaches earth?

Explanation:

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Valence electrons are the electrons in the outermost shell of an atom. They are important because they determine an atom's chemical reactivity and bonding behavior. Atoms tend to gain, lose, or share valence electrons to achieve a stable electron - configuration, usually a full outer shell.

Step1: Recall the wave - speed formula

The speed of light $c$ is related to frequency $f$ and wavelength $\lambda$ by the formula $c = f\lambda$, where $c = 3\times10^{8}\ m/s$. We need to solve for $f$.

Step2: Rearrange the formula for frequency

$f=\frac{c}{\lambda}$

Step3: Substitute the values

Given $\lambda = 2.67\times 10^{-13}\ m$ and $c = 3\times10^{8}\ m/s$, we have $f=\frac{3\times 10^{8}}{2.67\times 10^{-13}}$
$f=\frac{3}{2.67}\times10^{8 + 13}\approx1.12\times 10^{21}\ Hz$

Answer:

Valence electrons are the electrons in the outermost shell of an atom. They are important for determining an atom's chemical reactivity and bonding behavior.

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