The text says, "refugee and immigrant children in canada have significant similarities."what does significant mean?

Significant would mean noticeably or maybe even obviously. Maybe even size ably. Just flat out big or large.

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.