What name is assigned to these types of atoms that have an atomic number of 31

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Imagine that twenty i.u.’s of enzyme z were catalyzing the above reaction for one minute, under vmaxconditions, in a 3.00 ml assay volume. the assay is buffered with 20 mm phosphate buffer, ph 7.60. what will the ph be at the end of that one minute?

Draw the structure for 5-isopropyl-2-methyl-3-nonene