Answer: Changes in atomic radius and effective nuclear charge.
- A Changes in atomic radius and effective nuclear charge
- B Atomic mass alone, independent of nuclear charge or radius
- C The number of neutrons present in the nucleus
- D Electron configuration alone, independent of radius or charge
Correct answer: A. Changes in atomic radius and effective nuclear charge
Explanation: Smaller atoms with higher Zeff attract bonding electrons more strongly, increasing electronegativity.
The complete modern periodic table (118 elements). Image: Cepheus et al., Public Domain, via Wikimedia Commons.
Concept context
The periodic table organises all 118 elements by atomic number and similar properties. Study periodic trends like atomic radius, ionization energy, and electronegativity, and learn how an element's position predicts its behaviour.
Read the full Classification of Elements and Periodicity in Properties notes →