What is the rationale for the atomic size trend down a column on the periodic table? options:

1. Effective nuclear charge decreases top to bottom.

2. Effective nuclear charge increases top to bottom.

3. Valence shell number decreases top to bottom.

4. Valence shell number increases top to bottom.

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.