Anyone knows how to do this-

Explanation:

The number of protons in the element C^12 (Carbon) is 6, number of electrons 12 and number of Neutrons is 6, same as the number of protons it contains

C^13 has 13 electrons, 6 protons and 7 Neutrons this one's neutron number is different from proton number because it's an isotope

Na^-1 has gained an electron so the number of electrons it has = 24 and the number of protons shown as 11 which means there are 23 - 11 = 12 Neutrons

O^-2 has gained two electrons and got 18 electrons in total, 8 protons and 8 neutrons

c, liquids evaporate, creating a gas

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