Answer:
Both metals and non metals.
Explanation:
The correct formula of baking soda is NaHCO₃,
An element is considered to be metal if it is able to give electron easily due to very low ionization energy.
A non metal is ready to accept electron easily due to high electron affinity.
In sodium bicarbonate :
Na: Sodium : metal
H : Hydrogen: non metal (although placed with first group, alkali metals, in the periodic table as it readily loses electron like metals)
C: Carbon: Non metal
O : Oxygen : Non metal.
So the compound contains both metals and non metals.