Answer:
C. 1 and 3 only
Explanation:
In this element representation';
The superscript (23) s the mass number. Mass Number = Protons + Neutrons
-The subscript (11) is the atomic number.
Atomic Number = Protons
This means;
Number of Protons = 11
Number of Neutrons = 23 - 11 = 12
Number of electrons = 11 (Since it is a neutral atom)
Also sodium belongs to group 1 hence number of outer electrons = 1
The correct option is;
C. 1 and 3 only
