hydrogen
The atom that has the lowest mass is hydrogen. So assuming the same numbers of atoms in each element, hydrogen would be the element with the lowest mass.
Hydrogen is the only primordial element in the universe. All the other elements formed inside stars from hydrogen or from other secondary elements, by nuclear fusion. Hydrogen has the least number of protons in its nucleus of all the elements, and hence has the lowest atomic number, one.
All elements are pure substances.
Oxygen is an element and is not composed of other elements.
A stable element is any non-radioactive element. All elements before element atomic number 84 (not including 84) - Polonium (Po) are stable elements.
Hydrogen
Hydrogen with 0.09 density
Hydrogen is the least dense of all the elements and all other known substances.
Hydrogen has the lowest density of all elements. Density of it is 0.084 gm-3. It is a diatomic gas.
Hydrogen because it is only one proton and one electron.
Helium melting point: -272,2 0C Rhenium boiling point: 5 596 0C
The atom that has the lowest mass is hydrogen. So assuming the same numbers of atoms in each element, hydrogen would be the element with the lowest mass.
Hydrogen: 0,089 88 g/L at 0 0C and 101,325 kPa.
hydrogen
Helium is the second lightest element. Helium has the lowest boiling point among all the elements. It is chemically inert.
The element which has been measured to have the lowest density is hydrogen. Not only is hydrogen the least dense element, it is also the most plentiful on earth.
All elements have a specific signature, whereby one element is exactly different from another element.