Question

peordic table of 20 to 40 elements with atomic mass atomic no and with all the things ..​

Answer 1

Explanation:

calcium atoms

For example, all calcium atoms have an atomic number of 20 but there are three isotopes of calcium - 39, 40, and 42. (How many neutrons does each isotope possess?)

...

Structure of an Atom.

Sub Shell Max Electrons

f 14