Question

the group number of an element on the periodic table corresponds to the number of valence electrons in an atom of that element.
a true
b false

Explanation:

For main - group elements (groups 1, 2, and 13 - 18 in the modern periodic table), the group number corresponds to the number of valence electrons. For example, group 1 elements (alkali metals) have 1 valence electron, group 2 elements (alkaline earth metals) have 2 valence electrons, group 13 elements have 3 valence electrons, and so on. However, for transition metals (groups 3 - 12), this rule does not hold as they have valence electrons in \(d\) - orbitals as well and their valence electron count is more complex. But if we consider the statement in a general sense for main - group elements (which is often the context in basic chemistry when such a statement is made without specifying transition metals), the statement is True.

Answer:

A. True