Answer:-
.
Explanation:- Atomic number for fluorine(F) is 9 and it's electron configuration is
.
is formed when F loses one electron from it's valence shell.

Second shell is the valence shell for fluorine and so it loses one electron from 2p to form
and the electron configuration of the ion becomes
.
5.6 Al(OH)3
5.6 Al, 16.8 O, 16.8 H
16.8 mols of oxegyn in 5.6 mols of Al(OH)3
Answer:
Lichens can be used as air pollution indicators, especially of the concentration of sulphur dioxide in the atmosphere. Lichens are organisms that grow in exposed places such as rocks or tree bark. They need to be very efficient at absorbing water and nutrients to grow there.