Question

The mass number of an element is 18. It contains 7 electrons. What is the number of protons and neutrons? What is an atomic number of this element?

Answer 1

No.of protons=no.of electrons
=7
No.ofneutrons=mass number - no.of protons
=18-7=11

Answer 2

Number of protons =Number of electrons Number of neutrons=mass number-number of protons =18-7=11
atomic number is 11
Element is sodium