How do modern scientists describe the makeup of matter?

Any substance made out of iotas, that has mass and possesses space. Matter ought not be mistaken for mass, as the two are not the same in current material science. Matter is itself a physical substance of which frameworks might be formed, while mass isn't a substance but instead a quantitative property of issue and different substances or frameworks. While there are diverse perspectives on what ought to be viewed as issue, the mass of a substance or framework is the same regardless of any such meaning of issue. Another distinction is that issue has an "inverse" called antimatter, however mass has no inverse—there is no such thing as "hostile to mass" or negative mass. Antimatter has the same (i.e. positive) mass property as its typical issue partner.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

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