To address this question, we need to correctly complete the given gaps based on our knowledge of the Periodic Table and the trends in melting points for Group I and Group VII elements.
1. Understanding the arrangement of elements:
Elements in the Periodic Table are arranged in order of increasing atomic number. The atomic number corresponds to the number of protons in an atom's nucleus. Therefore, the word that correctly completes gap 1 is proton.
2. Melting points of Group I elements:
Group I elements are the alkali metals (such as lithium, sodium, potassium, etc.). As we move down the group from lithium to cesium, the melting points of these elements decrease. So, the word that correctly fills gap 2 is decrease.
3. Melting points of Group VII elements:
Group VII elements are the halogens (such as fluorine, chlorine, bromine, etc.). As we move down the group from fluorine to iodine, the melting points of these elements also decrease. Thus, the word that correctly completes gap 3 is also decrease.
We can now match these observations to one of the given choices in the table:
- Gap 1: proton
- Gap 2: decrease
- Gap 3: decrease
By examining the choices:
- A: nucleon, decrease, increase
- B: nucleon, increase, decrease
- C: proton, decrease, increase
- D: proton, increase, decrease
We see that none of the given choices match the exact combination of "proton, decrease, decrease" in gaps 1, 2, and 3.
However, upon closer inspection, the closest match is:
- D: proton, increase, decrease
Thus, the best choice that matches our detailed understanding and the options provided is D.
Therefore, the correct choice is:
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