Question

All the elements in a period of a modern periodic table have the same ______

• A. Valence shell
• B. Valence electrons
• C. Atomic number
• D. Mass number

Answer 1

The correct option is A

Valence shell

The shell of an atom that contains the valence (last) electrons is called the valence shell. All the elements in a period of a periodic table have the same number of filled shells and hence also the valence shell.