Osmium is the most dense element.
The density rho of Hahnium (Dubnium) is still unknown. The density of Osmium is rho = 22,610 kg/m3 or 22.61  g/cm3.
iridium osmium platinum plutonium
Helium is heavier than hydrogen. Hydrogen is the lightest and simplest element in the periodic table, while helium is the second lightest element.
Any one element can ONLY have a single fixed number of protons. Th only element with a number of protons that sits between 50 and 75 in group 17 of the periodic table is Iodine (I), with 53 protons.
If "heavier than" in the question is interpreted to mean "has an atomic mass greater than", the answer is nitrogen
No, atomically Iron is a heavier element
The density rho of Hahnium (Dubnium) is still unknown. The density of Osmium is rho = 22,610 kg/m3 or 22.61  g/cm3.
Osmium is the densest element at 22.61 g/cm3 assuming standard conditions.
rhenium
Osmium is much denser than an elephant. Which is heavier depends on how much elephant and how much osmium you're talking about. An elephant-sized pile of osmium would weigh over 20 times as much as an elephant-sized elephant would.
Osmium and iridium are both heavier than gold.
iridium osmium platinum plutonium
Note that a higher atomic mass does not necessarily imply a higher density (it does tend to work that way, but there are lots of counterexamples, and for example both osmium and iridium are considerably denser than the much heavier... in terms of atomic mass... uranium). So depending on what you mean by "heavy", the answer might be slightly different.
Osmium tetroxide is heavier than mercury, with a greater density of 4,910 kg/m^3 compared to mercury's density of 13,600 kg/m^3.
copper
Osmium is slightly more dense than Iridium by a small fraction.
The density of iodine at room temperature is 4,933 g/cm3. This is not a high density.