What is a group of atoms that join together?

b.final

i would say b

explanation:

but i think i would need more information than that

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

catya your not at all which answer i've seen you do this on another question!