The following properties can be used to distinguish elements from one another: 1 metallic character, 2 number of electron shells in an atom, 3 number of protons in an atom, 4 total number of electrons in an atom. Which two of these properties increase across a period of the Periodic Table?
- A1 and 2
- B1 and 3
- C2 and 4
- D3 and 4