Mass number is the total number of Protons and Neutrons. Simply subtract 85 from 210. 210-85=125 neutrons
Answer:

Explanation:
Suppose an electron makes transition from n initial (ni) to n final (nf) then formula for wavelength is given by,

Where,
- λ is wavelength of photon
- Rʜ is rydberg constant, the value of Rʜ is
109690 Cm-¹ in <em>Puri Sharma Pathania</em> standard book of physical chemistry &
109737 Cm-¹ according to <em>Wikipedia</em>
- Z is the atomic number of atom, for hydrogen Z =1,
& according to given data, ni = 5, nf = 3
Solution:
Let's solve for wavelength,
Substituting all the given data in above formula,






Now we know that, 1 cm = 10000000 nm,
Converting the wavelength from Cm → Nm




Answer:
They have all the same number of protons and electrons ( 6)
Explanation:
Carbon 12, Carbon 13 and Carbon 14 are all isotopes of Carbon.
The definition of an isotope is: They have the same number of protons (and electrons), but a different number of neutrons. Different isotopes of the same element have different masses.
Carbon 12 means an isotope with mass 12 u
it has 6 protons,(and 6 electrons) and 6 neutrons : 6 neutrons + 6 protons = 12
Carbon 13 is an isotope with mass 13 u
It has the same amount of protons ( and electrons) as Carbon 12, so 6 protons and 6 electrons
13 - 6 = 7 ⇒ Carbon 13 has 7 neutrons
Carbon 14 is an isotope with mass 14
it has the same of protons ( and electrons) as Carbon 12 and Carbon 13, so 6 protons and 6 electrons
14 - 6 = 8 ⇒ Carbon 14 has 8 neutrons
We can conclude that Carbon 12, Carbon 13 and Carbon 14 are 3 isotopes of Carbon. They all have the same number of protons (and electrons) = 6.
This means the isotopes will also have the same atomic number, because they are all isotopes of the same element.
We are given with the percentage composition of oxygen in an oxide from phosphorus and oxygen equal to 43.6 percent. that is the phosphorus is equal to 56.4 percent. we divide each with the molar mass and divide each with the smaller quantity. P then is equal to 1 and O is equal to 1.5. In this case, the empirical formula is P2O3.