Answer:
when an electron jumped into higher energy level from lower energy level it must absorbed the energy because with small amount of energy it can not jumped into higher energy level.
when it came back to lower energy level it release extra energy.
Explanation:
The electron is jumped into higher level and back into lower level by absorbing and releasing the energy.
The process is called excitation and de-excitation.
Excitation:
When the energy is provided to the atom the electrons by absorbing the energy jump to the higher energy levels. This process is called excitation. The amount of energy absorbed by the electron is exactly equal to the energy difference of orbits. For example if electron jumped from K to L it must absorbed the energy which is equal the energy difference of these two level. The excited electron thus move back to lower energy level which is K by releasing the energy because electron can not stay longer in higher energy level and comes to ground state.
De-excitation:
When the excited electron fall back to the lower energy levels the energy is released in the form of radiations. this energy is exactly equal to the energy difference between the orbits. The characteristics bright colors are due to the these emitted radiations. These emitted radiations can be seen if they are fall in the visible region of spectrum
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We can find the number of moles of PH₃ using ideal gas law equation
PV = nRTwhere
P - standard pressure - 101 325 Pa
V - volume - 250 x 10⁻⁶ m³
n - number of moles
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 273 K
substituting the values in the equation
101 325 Pa x 250 x 10⁻⁶ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 273 K
n = 0.011 mol
therefore mass of PH₃ = 0.011 mol x 34 g/mol = 0.374 g
mass of PH₃ is 0.374 g
Answer:
To prevent the mixture from separating substances called emulsifiers can be added. These help to form and stabilise the emulsions, preventing or slowing the water and fat/oil from separating. ... The hydrophilic end of the emulsifier molecule is attracted to the water and the hydrophobic end is attracted to the fat/oil.
<span>The option A is correct answer. The isotopes are X and Y. The isotopes are those which have same atomic number but different mass number. Since atomic number has same number of protons or electrons. Thus, isotopes have same number of protons or electrons. Therefore, X and Y are isotopes.</span>
