Humber Admissions Practice Test

What do vertical columns on the periodic table represent?

1. Groups of elements

2. Periods of elements

3. Molecular structures

4. Electrons in orbitals

The correct answer is: Groups of elements

Vertical columns on the periodic table represent groups of elements, which are also known as families. Elements within the same group share similar chemical properties and exhibit trends in their physical and chemical characteristics due to their similar valence electron configurations. For example, elements in Group 1, known as alkali metals, all have one electron in their outermost shell, which leads to them having similar reactivity and forming similar compounds. In contrast, periods on the periodic table are represented by horizontal rows, and they indicate the principal energy levels of the electrons in the atom. Molecular structures do not correspond directly to the arrangement of elements on the periodic table; instead, they describe how atoms are bonded together in molecules. Finally, while electrons in orbitals are indeed related to the arrangement of elements, the periodic table does not represent electrons in orbitals directly as it outlines the arrangement of the elements based on their atomic structure and properties rather than the specifics of electron configurations.