# What is the secondmost abundant element in the universe?

Mar 12, 2017

Helium

#### Explanation:

The most abundant element is hydrogen, making up about $90$%, then helium at about $10$%. All other elements put together are less than $1$%.

The most abundant isotope of helium is ""^4 He, with a mass about $4$ times that of the most common isotope ""^1 H of hydrogen. In terms of mass, helium makes up about $24$% of the mass of the universe.