Approximately how many metalloids are commonly recognised in the modern periodic table in standard school level chemistry?

Introduction / Context:
Metalloids form a small but important group of elements in the periodic table that show properties intermediate between metals and non metals. They are often used in semiconductors, glass, alloys and other specialised applications. At the school level, a standard list of metalloids is usually taught, and students are sometimes asked to recall how many such elements there are. This question focuses on the approximate count of commonly recognised metalloids in the modern periodic table as presented in typical textbooks.

Given Data / Assumptions:

• Metalloids lie along the diagonal zigzag line separating metals and non metals in the periodic table.
• Commonly listed metalloids include boron, silicon, germanium, arsenic, antimony and tellurium.
• Some sources also include polonium or astatine, but school level lists often focus on the core group.
• We are concerned with the number used in standard general science and school chemistry materials.

Concept / Approach:
The most commonly taught list of metalloids at school level includes six elements: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb) and tellurium (Te). These elements lie along the border between metals and non metals and exhibit intermediate properties. While some advanced sources debate adding more elements, the typical educational answer for how many metalloids there are is six. The approach is to recall this standard list and count its members, then select the option that matches this number.

Step-by-Step Solution:
Step 1: List the commonly accepted metalloids: boron, silicon, germanium, arsenic, antimony and tellurium. Step 2: Count these elements: boron is one, silicon two, germanium three, arsenic four, antimony five and tellurium six. Step 3: Some sources may also mention polonium or astatine, but in most school textbooks these are not included in the basic metalloid list. Step 4: Therefore, at this level, the number of metalloids is usually given as six. Step 5: Compare this count with the options and choose six metalloids as the correct answer.

Verification / Alternative check:
If you look at a periodic table with metal, metalloid and non metal colours indicated, you typically see a zigzag line with six elements highlighted as metalloids. Chemistry textbooks for secondary school also usually include a table where boron, silicon, germanium, arsenic, antimony and tellurium are listed together under the heading metalloids. They also illustrate their intermediate properties such as semiconducting behaviour and moderate electrical conductivity. These consistent references support the answer of six metalloids for exam purposes.

Why Other Options Are Wrong:
Option A, 5 metalloids, undercounts the usual group and would exclude one of the standard elements. Option B, 4 metalloids, is too low and does not reflect the usual educational list. Option C, 7 metalloids, might be used in some advanced contexts if elements like polonium or astatine are included, but this is beyond normal school level practice. Option E, 10 metalloids, is far above any commonly accepted count. Only option D correctly matches the widely taught number of six metalloids in the modern periodic table at this level.

Common Pitfalls:
Students may confuse the exact count because some periodic tables and references vary slightly, especially when they include borderline elements. Another pitfall is to misinterpret elements along the zigzag line and accidentally count non standard ones. To avoid confusion in school examinations, it is best to memorise the commonly listed six metalloids and their symbols. Remembering that they include boron and silicon, which are important in glass and electronics, along with germanium, arsenic, antimony and tellurium, will help you recall both their names and that there are six of them.

Final Answer:
The number of metalloids commonly recognised in the modern periodic table at school level is 6 metalloids.