Question

mass number 2 exampels​

Answer 1

Answer:

Example, atomic number of sodium is 11. ii) Mass number is the number of protons and neutrons in the nucleus taken together. For example, mass number of sodium is 23 g/mol. iii) Isotopes are elements with the same atomic number but different mass numbers.

Answer 2

Answer:

Helium has an atomic number of 2 since it has two protons in its nucleus. Lithium has an atomic number of 3 since it has three protons in its nucleus.