The electronic configuration of a ground-state Cr-atom :
1s²2s²2p⁶3s²3p⁶4s²3d⁴
<h3><u>What are electronic configurations?</u></h3>
The arrangement of an atom's or molecule's (or other physical structure's) electrons in their atomic or molecular orbitals is known as the electron configuration in atomic physics and quantum chemistry. For instance, the neon atom's electron configuration is 1s² 2s² 2p⁶, which means that 1, 2 and 6 electrons, respectively, are present in each of the 1s, 2s, and 2p subshells.
According to electronic configurations, each electron moves individually within an orbital while being surrounded by an average field produced by all other orbitals. Slater determinants or configuration state functions are used to mathematically characterize configurations.
To view more about electronic configurations, refer to:
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<u>Answer:</u> The time taken by the reaction is 84.5 seconds
<u>Explanation:</u>
The equation used to calculate half life for first order kinetics:

where,
= half-life of the reaction = 9.0 s
k = rate constant = ?
Putting values in above equation, we get:

Rate law expression for first order kinetics is given by the equation:
......(1)
where,
k = rate constant = 
t = time taken for decay process = 50.7 sec
= initial amount of the reactant = ?
[A] = amount left after decay process = 0.0741 M
Putting values in equation 1, we get:
![0.077=\frac{2.303}{50.7}\log\frac{[A_o]}{0.0741}](https://tex.z-dn.net/?f=0.077%3D%5Cfrac%7B2.303%7D%7B50.7%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B0.0741%7D)
![[A_o]=3.67M](https://tex.z-dn.net/?f=%5BA_o%5D%3D3.67M)
Now, calculating the time taken by using equation 1:
![[A]=0.0055M](https://tex.z-dn.net/?f=%5BA%5D%3D0.0055M)

![[A_o]=3.67M](https://tex.z-dn.net/?f=%5BA_o%5D%3D3.67M)
Putting values in equation 1, we get:

Hence, the time taken by the reaction is 84.5 seconds
Answer:
a) Germanium = 5.76 x 〖10〗^11 〖cm〗^(-3) , Semiconductor is n-type.
b) Silicon = 2.25 x 〖10〗^5 〖cm〗^(-3) , Semiconductor is n-type.
For clear view of the answers: Please refer to calculation 5 in the attachments section.
Explanation:
So, in order to find out the concentration of holes and electrons in a sample of germanium and silicon which have the concentration of donor atoms equals to 〖10〗^15 〖cm〗^(-3). We first need to find out the intrinsic carrier concentration of silicon and germanium at room temperature (T= 300K).
Here is the formula to calculate intrinsic carrier concentration: For calculation please refer to calculation 1:
So, till now we have calculated the intrinsic carrier concentration for germanium and silicon. Now, in this question we have been given donor concentration (N_d) (N subscript d), but if donor concentration is much greater than the intrinsic concentration then we can write: Please refer to calculation 2.
So, now we have got the concentration of electrons in both germanium and silicon. Now, we have to find out the concentration of holes in germanium and silicon (p_o). (p subscript o)
Equation to find out hole concentration: Please refer to calculation 3. and Calculation 4. in the attachment section.
Good Luck Everyone! Hope you will understand.
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