Multiple Choice
Which atom in each group has the smallest atomic radius? Na, Si, Cl; Be, Mg, Ca?
10. Periodic Properties of the Elements
Periodic Trend: Atomic Radius
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
In moving from top to bottom in the same column on the periodic table, what trend is expected for atomic size?
A
Increase because the nucleus is getting stronger.
B
Increase because electrons are being placed in higher n-values.
C
Decrease because the nucleus is getting stronger.
D
Increase because electrons are being added to degenerate orbitals.
E
Decrease because electrons are being placed in higher n-values.
Verified step by step guidance1
Identify the trend in atomic size as you move down a column in the periodic table. This involves understanding how atomic size changes with the addition of electron shells.
Recall that atomic size generally increases as you move down a group in the periodic table. This is because electrons are added to orbitals with higher principal quantum numbers (n-values), which are further from the nucleus.
Consider the effect of electron shielding. As new electron shells are added, the inner electrons shield the outer electrons from the full effect of the nuclear charge, allowing the outer electrons to be further away from the nucleus.
Understand that while the nuclear charge does increase as you move down a group, the effect of increased electron shielding and higher n-values outweighs the increased nuclear charge, leading to an increase in atomic size.
Conclude that the correct explanation for the increase in atomic size down a group is due to electrons being placed in higher n-values, which are further from the nucleus, resulting in a larger atomic radius.
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