Question

Which of the following are isotopes, choose all that apply.

Element X with atomic number 10 and atomic mass 21

Element Y with atomic number 11 and atomic mass 21

Element Z with atomic number 10 and atomic mass 22

Element M with atomic number 12 and atomic mass 21

Answer 1

Element X with atomic number 10 and atomic mass 21

Element Z with atomic number 10 and atomic mass 22

Step-by-step explanation:

Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.

• Isotopes of an element have the same electronic configuration.
• They share the same chemical properties
• They only differ in their masses.

So, Element X and Z with atomic number 10 which is their number of electrons are isotopes. Their mass number, 21 and 22 differs.