My calculations say it'll take 600 hours???
The element symbol in chemistry comprises atomic number and mass number.
Atomic number is written on the top of element and mass number is written at the bottom.
For eg:
If Y is an element that is having atomic number a and mass number x. Then its denotion will be:
ᵃYₓ.
So here ⁹F₁₈.₉₉
Here 18.99 will denote mass number while 9 will denote atomic number.
Na2SO4(aq)+Ba(NO3)2(aq)------------2NaNO3(aq)+BaSO4(s)
Answer:
Electrons around the nucleus
