Learning Path
Question & Answer1
Understand Question2
Review Options3
Learn Explanation4
Explore TopicChoose the Best Answer
A
Increased nuclear charge pulls electrons closer to the nucleus
B
Electrons are added to the outer shell, increasing size
C
Shielding effect increases, causing a larger radius
D
Electrons are lost during bonding, leading to a smaller radius
Understanding the Answer
Let's break down why this is correct
Answer
The atomic radius is the distance from the nucleus to the outermost electrons. When you move from left to right across a period, each element has one more proton in its nucleus but the inner electrons that shield the outer electrons stay roughly the same. Because the nuclear charge increases while shielding remains constant, the attractive force on the outer electrons grows, pulling them closer to the nucleus. For example, sodium (Na) has a larger radius than chlorine (Cl) even though both have the same number of electron shells, because Cl’s nucleus has more protons and pulls its electrons tighter. Thus the atomic radius steadily decreases across a period.
Detailed Explanation
When a new element is added to the same energy level, its nucleus gains another proton. Other options are incorrect because Adding electrons to the outer shell does not mean the atom grows; Shielding comes from inner electrons.
Key Concepts
Atomic Radius
Nuclear Charge
Periodic Trends
Topic
Periodic Properties
Difficulty
easy level question
Cognitive Level
understand
Practice Similar Questions
Test your understanding with related questions
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