Experiements on the emission spectra of______atoms gave rise to a fourth quantum number describing an electron in an atom.
(i) `H` (ii) `Na`
(iii) `Ag` (iv) `I`

Options

A. `(i),(iv)`
B. `(ii),(iii)`
C. `(i),(ii),(iii),(iv)`
D. `(ii),(iii),(iv)`

Answer

C

Explanation

Each has one unpaired electron. Experiments revealed that lines in the emission spectra could be split by the application of an external magnetic field. The only ways scientists could explain these results was to assue that electrons behave like tiny bar magnets with north and south poles. If electrons are thorught of as spinning on their own axes, as the earth does, their magnetic properties can be accounted for. According to the electromagnetic theory, a spinnig charge generates a magnetic field, and it is this motion that causes the electron to behave like a magnet. There are two possible spinning motions of an electron-one clockwise and the other counterclockwise. to take the electron spin into account, we use a fourth quantum number called the electron spin quantum number `(m_(s))`, which has a value of `+1//2` or `-1//2`. These values corresponds to the two possible spinning motions of the electron.