In the periodic table, which of the following elements has chemical properties most similar to those of beryllium?

Introduction / Context:
This question tests the concept of periodicity, specifically how elements in the same group share similar chemical properties. Beryllium is an alkaline earth metal in group 2 of the periodic table. Elements in the same group typically have the same number of valence electrons and therefore display similar chemical behaviour. By comparing the group positions of manganese, calcium, and helium, we can determine which element is most similar to beryllium.

Given Data / Assumptions:
- Beryllium is the reference element whose properties we want to match.
- Options include manganese, calcium, both manganese and calcium, and helium.
- We assume a standard long form periodic table where group 2 contains alkaline earth metals.

Concept / Approach:
Elements in the same vertical column or group have the same valence electron configuration and hence very similar chemical properties. Beryllium (Be) is in group 2 (IIA), the alkaline earth metals. Calcium (Ca) is also in group 2, below magnesium. Manganese (Mn) is in group 7 (VIIB) among the transition metals and has very different chemistry from beryllium. Helium (He) is a noble gas in group 18 and is chemically inert compared with beryllium. Therefore, we expect calcium, the group 2 element, to have properties most similar to beryllium.

Step-by-Step Solution:
Step 1: Note that beryllium has atomic number 4 and belongs to group 2, the alkaline earth metals.
Step 2: Calcium has atomic number 20 and is also in group 2, directly below magnesium. It has two valence electrons, like beryllium.
Step 3: Manganese has atomic number 25 and is located in the transition series, group 7, which gives it complex d block chemistry unlike the s block alkaline earth metals.
Step 4: Helium has atomic number 2 and is a noble gas in group 18, with a full shell and very low chemical reactivity.
Step 5: Since group membership is the best guide to similar chemical behaviour, calcium, as a fellow group 2 alkaline earth metal, is most similar to beryllium.
Step 6: The option Both A and B cannot be correct because manganese is not similar to beryllium in chemical properties.

Verification / Alternative check:
Textbooks describe typical reactions of alkaline earth metals such as beryllium, magnesium, and calcium, including formation of oxides, hydroxides, and salts with a +2 oxidation state. Calcium and magnesium behave in patterns similar to beryllium, though beryllium also shows some unique behaviour. Manganese, on the other hand, displays many oxidation states and forms coloured transition metal complexes, unlike the simple s block chemistry of beryllium. Helium is largely inert. These comparisons confirm that calcium is the element whose chemistry is closest to beryllium among the options.

Why Other Options Are Wrong:
- Manganese: This is a d block transition metal with very different chemistry from the s block alkaline earth metals. It is not similar to beryllium in standard reactions.
- Both A and B: Since manganese is not similar to beryllium, this combined option cannot be correct.

Why Other Options Are Wrong (continued):
- Helium: As a noble gas, helium is chemically inert and does not share the reactive metallic behaviour of beryllium at all.

Common Pitfalls:
A frequent mistake is to focus on approximate atomic size or mass rather than group position. Another error is to assume any metal might have similar properties, ignoring the role of valence electrons. Always use the periodic table groups to identify similar behaviour, since group members have the same outer electron configuration and show comparable chemical reactions. This makes it straightforward to connect beryllium with other group 2 metals such as calcium.

Final Answer:
Calcium is the element whose properties are most similar to those of beryllium.