Question

elements have similar behavior when
○ they are on the left/right to each other on the ptote.
○ they are above/below each other on the ptote.
○ they were identified in the same century.

Explanation:

In the periodic table (assuming "PTOTE" is a typo for "periodic table"), elements in the same group (vertical column, above/below each other) have similar chemical behavior due to the same number of valence electrons. Elements left/right (same period) have different properties, and identification century doesn't relate to behavior. So the correct option is the one about being above/below.

Answer:

B. they are above/below each other on the PTOTE. (Note: Assuming "PTOTE" is a typo for "periodic table", the correct reasoning is that elements in the same group (vertical, above/below) have similar properties due to valence electron configuration. The first option refers to period (horizontal, left/right) with varying properties, and the third is irrelevant to chemical behavior.)