Question

what is the meaning of 1s2 electron configuration (tell what 1 means, the s means and teh superscript of 2 means)?

Answer 1

There are two electrons in the 1s orbital of an atom.

Answer 2

but what does it all mean?

Answer 3

Its the arrangement of electrons.

Answer 4

do you know about s p d f, the first shell K has only the s orbital, hence 1s: the s orbital in any of the shells able to carry only 2 electrons at most, hence 1s superscript 2, . if you take the electron config for the atom of Lithium is 1s superscript2 2s superscript 1. Sodium 1s2, 2s2 2p6, 3s1. it has 2 electrons for shell K, 8 for L shell (i.e 2 on s and 6 on p orbitals) and 1 electrone on s orbital of the 3rd shell which is M