What is the electron arrangement of K

What sort of evidence would support at least one of the components of the

Yuki888 [10]

Answer:

(not sure) The origin of all cells observed can be traced to previous cells

Explanation:

- not all cells convert energy (?) (this I'm not sure but think so? might be wrong tho)

- not all cells have cell walls e.g. animal cells only have the cell membrane, no cell wall

- Rocks and other nonliving things are composed of cells: non living things are composed of the elements and not cells (unless they were previously alive, then they contain dead cells)

8 0

3 years ago

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

Phantasy [73]

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:

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

$\mathtt{E_7 =-0.27755 \ eV}$

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

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

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

4 0

2 years ago

Two solids, A and B, are located in the same family on the periodic table. A sample of each is placed in a beaker of HCL. Substa

Vlad [161]

What do the bubbles indicate? chemical reaction with HCl, release of H2(g)

Where the substances are located in relation to one another on the periodic table and the activity series? A is above B on the periodic table but B is above A in the activity series.

The name of the family the substances could be in ? alkaline earth, alkali metals. Either group 1 or group 2.

What substance will have a larger atomic radius? B
What substance will have a larger ionization energy? A

4 0

2 years ago

The graph represents the heating of water in a pot. At 150 seconds, the water has just reached a boil. If the heat is left on, w

navik [9.2K]

Temperature will raise and water will evaporate

5 0

2 years ago

An environmental scientist developed a new analytical method for the determination of cadmium (cd^2+) in mussels. To validate th

Anettt [7]

Answer:

The method is accurate in the calculation of the $Cu^+2$

Explanation:

As a first step we have to calculate the average concentration of $Cu^+2$ find it by the method.

$\frac{0.782+0.762+0.825+0.838+0.761 }{5} =0.79 ppm$

Then we have to find the standard deviation:

$s=\sqrt{\frac{1}{N-1}\sum_{i=1}^N(x_i-\bar{x})^2}=0.0359$

For the confidence interval we have to use the formula:

μ=Average± $\frac{t*s}{\sqrt{n} }$

Where:

t=t student constant with 95 % of confidence and 5 data=2.78

μ= $0.79$ ± $\frac{2.78*0.0359}{\sqrt{5} }$

upper limit: 0.84

lower limit: 0.75

If we compare the limits of the value obtanied by the method (Figure 1 Red line) with the reference material (Figure 1 blue line) we can see that the values obtained by the method are within the values suggested by the reference material. So, it's method is accurate.

7 0

2 years ago