Answer to Question #118998 in Physical Chemistry for Umer Shemsu

Question

Compare size of lithium (atomic number=3) and boron ( atomic number=5) which one is larger and which one is smaller

Answer 1

Lithium is larger, boron is smaller. Because increasing atomic number means increasing positive nuclear charge, which attract the external electrons stronger. Since the electrons have the same mean quantum number (n = 2), the orbitals size decrease.