Question

valence electrons can be found via the periodic table by determining an elements

o a category (metal vs non - metal)
o b group
o c period
o d noble gas

Explanation:

In the periodic table, the group number (for main - group elements, excluding transition metals in a simple sense) gives the number of valence electrons. For example, group 1 elements have 1 valence electron, group 2 elements have 2 valence electrons, and group 17 (halogens) have 7 valence electrons.

• Option a: The category (metal vs non - metal) does not directly give the number of valence electrons. Metals can have different numbers of valence electrons (e.g., sodium (metal) has 1 valence electron, magnesium (metal) has 2). Non - metals also vary (e.g., carbon (non - metal) has 4, oxygen (non - metal) has 6).
• Option c: The period number gives the number of electron shells, not the number of valence electrons. For example, elements in period 2 have 2 electron shells, but valence electrons can range from 1 (lithium) to 8 (neon).
• Option d: Noble gases are a specific group (group 18), and while they have a full valence shell (8 electrons, except helium with 2), the term “noble gas” is too specific compared to the general concept of group number for valence - electron determination.

Answer:

B. Group