Comprehension Passage
The periodic table is a crucial tool in the field of chemistry. It organizes elements based on their atomic number, electron configuration, and recurring chemical properties. Elements are grouped in periods (horizontal rows) and groups (vertical columns). The elements in the same group have similar chemical properties due to the same number of valence electrons. For example, Group 1 elements, known as alkali metals, are highly reactive.
Why do elements in the same group exhibit similar chemical properties?
1
They have the same atomic mass.
2
They are located in the same period.
3
They have the same number of valence electrons.
4
They have the same density.