Question

elements have the same number of what when you move from the left of the periodic table to the right?

Answer 1

Electron shells hope this is right:)

Answer 2

Ans: On the periodic table, elements that have similar properties are in the same groups (vertical). From left to right, the atomic number (z) of the elements increases from one period to the next (horizontal). The groups are numbered at the top of each column and the periods on the left next to each row.