It will float, because it is almost weighs like a pen.
Methane is lighter than air, having a specific gravity of 0.554. It is only slightly soluble in water. It burns readily in air, forming carbon dioxide
and water vapour; the flame is pale, slightly luminous, and very hot.
The boiling point of methane is −162 °C (−259.6 °F) and the melting
point is −182.5 °C (−296.5 °F). Methane in general is very stable, but
mixtures of methane and air, with the methane content between 5 and 14
percent by volume, are explosive. Explosions of such mixtures have been
frequent in coal mines and collieries and have been the cause of many
mine disasters.
<span>The Ionization energy decreases because the full s orbital shields the electron entering the p orbital. This is known as "shielding", When each new electron experiences attraction from the nucleus and repulsion forces from the S orbitals, the net force on outer shell electrons is significantly smaller. Therefore, ionization energy decreases during these groups.</span>
Mg2+ is the positive ion of the neutral atom Mg. This means that the neutral atom Mg lost the two excess electrons in its outermost energy level and became a positive ion with the two excess positive charges. To become neutral again, the Mg2+ ion has to regain two electrons again to balance the negative charge with the excess two positive charges.
