Final answer:
Fluorine has the greatest electronegativity among the elements listed, with a value of 4.0. It's positioned in the upper right-hand corner of the periodic table, in line with the trend of increasing electronegativity across periods and decreasing down groups.
Step-by-step explanation:
The student is asking about electronegativity, which is the measure of an atom’s ability to attract electrons when it forms a compound. Among the elements listed (‘Hydrogen (H)’, ‘Sodium (Na)’, ‘Fluorine (F)’, ‘Carbon (C)’, and ‘Oxygen (O)’), fluorine has the greatest electronegativity with a value of 4.0. This high electronegativity indicates that fluorine has a strong tendency to gain electrons from other elements with lower electronegativities when they combine to form compounds.
The general trend in the periodic table shows that electronegativity increases across a period from left to right and decreases down a group. As fluorine is positioned in the upper right-hand corner of the periodic table, it possesses the highest electronegativity among the elements given. Thus, when considering the elements hydrogen, sodium, fluorine, carbon, and oxygen, fluorine is the one that most strongly attracts electrons.