Question

there are three isotopes of hydrogen. they are hydrogen-1 (sometimes called protium), hydrogen-2 (deuterium) and hydrogen-3 (tritium). what do these isotopes of hydrogen have in common? they have the same atomic number they have the same number of electrons they have the same number of protons they have the same number of neutrons they have the same mass number

Explanation:

Isotopes of an element have the same atomic number (number of protons). In neutral atoms, number of electrons = number of protons. So hydrogen isotopes share atomic number, electron - proton count, but differ in neutron - mass number.

Answer:

They have the same atomic number, They have the same number of electrons, They have the same number of protons