I am having trouble understanding 35Cl^-1 and 27Al^+3. How do i find out how many protons, neutrons, and electrons are in these? what are the ^-1 and ^+3 for? Thanks!

Question

sunnnystrong · Answer

Alright well this is a great question.

Chlorine has an atomic mass of 35 amu. The -1 indicates that the chlorine atom has a charge of -1. That simply means that there is another electron. Chlorine has an atomic number of 17. The atomic number indicates the number of protons in an atom. Therefore there must be 18 electrons and 28 neutrons.

sunnnystrong · Answer

The oxidation number of chlorine is also -1 so i guess it just depends how this was truly written. Exponents on atoms indicate electrical charges.

When asked questions like this
Remember:
Atomic number = number of protons
Atomic mass = number of protons and nuetrons (find nuetrons by subtracting atomic number from atomic mass)
Number of electrons = number of protons unless there is a charge as elements want to be neutral and exist at 0 charge.

hotlineblingbabe · Answer

@sunnnystrong so does that mean on the 27Al^+3, that it has a positive charge because it lost 3 electrons and the number of protons does not match the number of electrons?

sunnnystrong · Answer

Yep. If you see a charged species... that means it lost three electrons or gained a certain number of electrons depending on the charge (: