What is the name of this unstable isotope from number 9?

What is the composition, in atom percent, of an alloy that consists of 4.5 wt% pb and 95.5 wt% sn? the atomic weights for pb and sn are 207.19 g/mol and 118.71 g/mol, respectively.(a) 2.6 at% pb and 97.4 at% sn(b) 7.6 at% pb and 92.4 at% sn(c)97.4 at% pb and 2.6 at% sn(d) 92.4 at% pb and 7.6 at% sn

If you have 5.25 grams of methane (ch4), how many grams of co2 will you produce ?

According to the vsepr theory what is the shape of a molecule that has a central atom valence three other items with no lone pairs of electrons