Question

What is the same about all the elements in a single group on the periodic table?

The number of isotopes they form
The number of valence electrons in an atom
The number of core electrons in an atom
Their atomic mass

Answer 1

Respuesta:

declaracion 2 es la respuesta.

Explicacion: espero que esto ayude

Answer 2

Statement 2

Step-by-step explanation:

The number of valence electrons belonging to an atom is the same about all elements in a single group on the periodic table.