Which of the following species are isoelectronic: $Na, Na^+, F^-, F$?

$A$ monoatomic anion $(A^-)$ has $45$ neutrons and $36$ electrons. The atomic mass, group in the periodic table, and physical state at room temperature of the element $(A)$ are respectively:

$Ca$ has atomic number $20$ and atomic weight $40$. Which of the following statements is not correct about $Ca$ atom?

An element has an electronic configuration of $2, 8, 18, 1$. If its atomic weight is $63$,then how many neutrons will be present in its nucleus?

$Mg^{2+}$ is isoelectronic with

List the isotopes of hydrogen,carbon,and chlorine,and specify the number of protons,electrons,and neutrons for each.