How many minutes will it take for the quantity of n2o5 to drop to 1.9×10−2 mol ?

Missing question: The first-order rate constant for the decomposition of N2O5, 2N2O5(g)→4NO2(g) + O2(g) at 70°C is 6.82×10−3 s−1. Suppose we start with 2.70×10−2 mol of N2O5(g) in a volume of 1.8 L .
c₀(N₂O₅) = 0,027 mol ÷ 1,8 L.
c₀(N₂O₅) = 0,015 mol/L.
c(N₂O₅) = 0,019 mol/ 1,8 L = 0,01055 mol/L.
k = 6,82·10⁻³ s⁻¹.
ln c(N₂O₅) = ln c₀(N₂O₅) - k·t.
t = (ln c₀(N₂O₅) - ln c(N₂O₅)) ÷ k.
t = 0,35 ÷ 0,00682 s⁻¹.
t = 51 s = 0,86 min.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.