This video describes how to calculate relative molecular mass of any given solid and based on it how to make a solution of any concentration in any given volume. Video also describes to make solution of any standard acid solution if their concentration is…

This video explains the basic structure of atom , the subatomic particles, the difference in the structure of atom and an ion.
For more resources check:
t.me/camscience (IGCSE, need telegram app)
t.me/camscience2 (A levels)

This video defines and explains isotopes with examples, also teaches calculating relative isotopic mass and explains the uses of various radioisotopes.
for more resources:
t.me/camscience
t.me/camscience2 (needs telegram app)

this video explains the electronic structure/configuration of first 20 elements along with the diagramatic form.
for more resources check:
t.me/camscience
t.me/camscience2 (telegram app)