The atomic number in an element is usually how many protons the element has. For example, Hydrogen has a 1 on top of the H (on the periodic table), therefore, Hydrogen has 1 proton. Oxygen has an 8 on top of the O (on the periodic table) so therefore, Oxygen has 8 protons.
Although you have not provided the circled electron, I can help you with a wide explanation.
1) Atomic number of manganese is 25. That means that it has 25 protons and 25 electrons.
2) Those 25 electrons are distributed (electron configuration) as per the quantum rules:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
3) The most reasonable is that you have been asked to give the possible quantum numbers for an electron in the 4s or 3d.
4) Those are 7 electrons and these are their possible sets of quantum numbers:
i) For the two electrons in 4s:
n is the main energy level so n = 4
l tells the kind of orbital, which is s, so l = 0
ml is also 0 (it can be from -l to + l, so given that l i s0, ml is 0)
ms: one is +/12 and the other is -1/2 (this is the spin number).
ii) For the 5 electrons in 3d
n = 3
l can be 0, 1, or 2
if l = 0, then ml = 0
if l = 1, then ml can be -1, 0 , or 1 (from - l to + l)
ms can be either +1/2 or - 1/2 (spin)
Answer: The wavelength of the x-ray wave is 
Explanation:
To calculate the wavelength of light, we use the equation:
where,
= wavelength of the light = ?
c = speed of x-ray= 
= frequency of x-ray = 
Putting in the values:
Thus the wavelength of the x-ray wave is
The chemical formula of Iron (III) Sulfide is FeSO3. This element or compound has another name which is <span>ferric sulfide or sesquisulfide.</span>
The three group 4 elements that occur naturally are titanium, zirconium, and hafnium. The first three members of the group share similar properties; all three are hard refractory metals under standard conditions.
