Isotopes, Isobars and Isotones

Why do ${}_{17}{}^{35}\mathrm{Cl}$ and ${}_{17}{}^{37}\mathrm{Cl}$ have the same chemical properties? In what respect do these atoms differ?

Calcium and Argon are examples of a pair of _____.(isobars/isotones/isotopes)

State whether true or false. If false, correct the statement.

Isotopes of an element have different atomic numbers.

Change in the number of neutrons in an atom changes it to 

Among the following, the odd pair is 

Draw the model of the pair of isotones of Aluminium and Silicon.

Draw the model of the pair of isotones of Sodium and Magnesium.

Draw the model of the pair of isotones of Fluorine and Neon.

Draw the structures of the isotopes of oxygen ${\mathrm{O}}^{16}$ and ${\mathrm{O}}^{18}$.

Atomic number of oxygen $=8$.