Final answer:
The question appears to contain a typo regarding welding electrode classification; within the context of AWS standards, 'EXX14' would be considered a group F4 electrode due to its usability features and specific coating type.
Step-by-step explanation:
The question asks which one of the following electrodes is a group F4 electrode: a) EXX28 b) EXX14 c) EXX18 d) EXX11. The designation for welding electrodes such as those prefaced by "EXX" is based on the American Welding Society (AWS) numbering system. The 'E' indicates the electrode type, and the next two 'XX' numbers represent the tensile strength, the welding positions, and whether it is a solid or composite electrode.
However, the information presented seems to not match the question asked as the provided reference information is about chemical compounds and noble gases oxidation states rather than welding electrodes. Therefore, it is important to note that the presented options seem to be misplaced and are not relevant to determining the group F4 electrode. In the context of the American Welding Society's specification for electrodes, the 'F4' designator refers to the usability of the electrode, with 'F' indicating a specific type of current or polarity and '4' relating to the electrode's coating type and penetration characteristics.
Based on conventional AWS classification, an electrode with an AWS classification that matches "EXX14" would indeed be a group F4 electrode because the "14" designates that the electrode can be used in all positions with AC or DC+ currents and usually has an iron powder-titania coating which allows for a smooth weld with medium to deep penetration.