Question

In ${}_{17}^{35}Cl$ and ${}_{17}^{37}Cl$, which of the following is false?

• A. Both have $17$ protons
• B. Both have $17$ electrons
• C. Both have $18$ neutrons
• D. Both show same chemical properties

Answer 1

Answer: (C)

Both have $18$ neutrons

${}_{17}^{35}Cl$ and ${}_{17}^{37}Cl$ are isotopes.

They have the same atomic number (17), the same number of electrons (17) and the same number of protons (17).

They have different mass numbers (35 and 37 ) and different numbers of neutrons.

${}_{17}^{35}Cl$ has $35-17=18$ neutrons whereas ${}_{17}^{37}Cl$ has $35-17=20$ neutrons.

Note: Since both have the same number of electrons, they have the same chemical properties.