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Define atomic radius (covalent radius) - Leaving Cert Chemistry - Question b - 2005
Question b
Define atomic radius (covalent radius). Describe and account for the trend in atomic radii (covalent radii) of the elements: (i) across the second period, (ii) do... show full transcript
Worked Solution & Example Answer:Define atomic radius (covalent radius) - Leaving Cert Chemistry - Question b - 2005
Step 1
Step 2
Describe and account for the trend in atomic radii across the second period
Answer
Across the second period, the atomic radius decreases. This decrease can be attributed to the increase in nuclear charge as protons are added to the nucleus, which creates a stronger attraction between the nucleus and the electron cloud. Although additional electrons are also added, they are added to the same energy level and do not significantly shield each other, resulting in a greater effective nuclear charge that pulls the electrons closer to the nucleus.
Step 3
Describe and account for the trend in atomic radii down any group of the periodic table
Answer
Down any group of the periodic table, the atomic radius increases. This trend occurs because as we move down a group, additional electron shells are added. The increase in the number of filled shells means that the outermost electrons are farther from the nucleus, leading to a larger atomic radius, despite the increase in nuclear charge.