- Identify the positions of C, N, K, and Ca on the periodic table: C and N are in Period 2, while K and Ca are in Period 4.
- Apply periodic trends: Electronegativity increases from left to right across a period and decreases from top to bottom down a group.
- Compare the elements: Elements in higher periods (Period 2) have higher electronegativity than those in lower periods (Period 4), and within the same period, those further to the right (Nitrogen) are more electronegative than those to the left (Carbon).
- Conclude that nitrogen (N) has the highest electronegativity, which corresponds to option (c). The final answer is \(\boxed{c}\).
Explanation
- Analyzing Electronegativity and Periodic Trends
To determine which element among carbon (C), nitrogen (N), potassium (K), and calcium (Ca) attracts electrons most strongly, we must examine their electronegativity. Electronegativity is a measure of the tendency of an atom to attract a shared pair of electrons in a chemical bond. We look at their positions in the periodic table to apply known periodic trends.
- Periodic Table Positions and Trends
The position of each element in the periodic table is as follows:
- Carbon (C): Period 2, Group 14
- Nitrogen (N): Period 2, Group 15
- Potassium (K): Period 4, Group 1
- Calcium (Ca): Period 4, Group 2
Periodic trends dictate that electronegativity increases from left to right across a period and decreases from top to bottom down a group. Elements closer to the top-right of the periodic table (excluding noble gases) generally possess higher electronegativity.
- Comparing Electronegativity Values
Comparing the elements:
- Comparing Period 2 elements (C and N) with Period 4 elements (K and Ca): Since Period 2 elements have fewer electron shells than Period 4 elements, they exert a stronger pull on electrons. Thus, both C and N are more electronegative than both K and Ca.
- Comparing elements within the same period: Within Period 2, Nitrogen is to the right of Carbon, meaning Nitrogen has a higher electronegativity than Carbon.
- Comparing elements within the same group: Nitrogen is in Group 15 and Carbon is in Group 14 (Period 2), while Calcium is in Group 2 and Potassium is in Group 1 (Period 4). Nitrogen's position higher up and further right makes it the most electronegative among the given options.
- Conclusion
Based on the periodic trends, Nitrogen (N) has the highest electronegativity among the four elements listed. It is located at the top-rightmost position relative to the others, meaning it attracts shared electrons most strongly in a chemical bond. Therefore, the correct option is (c). The final answer is \(\boxed{c}\).
Examples
Understanding electronegativity is essential for predicting the polarity of molecules and the nature of chemical bonds. For example, in a molecule like ammonia (\(NH_3\)), the high electronegativity of nitrogen compared to hydrogen causes the nitrogen atom to pull electron density toward itself, creating a polar covalent bond. This property influences how substances dissolve, react, and interact in biological systems, such as how water molecules bond or how proteins fold in the human body.