An atomic mass unit is a unit of measurement that is used to measure the mass of atoms. The atomic mass unit (abbreviated: amu or u) is roughly equal to the mass of 1 proton<span> or 1 neutron. The unified atomic mass unit and the dalton are different names for the same thing. The dalton name is used more over time.</span>
Answer: Option (a) is the correct answer.
Explanation:
Poly means many and polyatomic ions means an ion(s) with two or more different atoms.
Out of the given options, phosphate ion is the polyatomic ion which has an ionic charge of 3-.
The formula depicting a phosphate ion is 
.
Whereas Nitrate, Sulfate, Hydroxide
, Bicarbonate does not carry or have a 3- ionic charge.
The answer is: " S²⁻ " .
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It is hard because we can't get past the crust, Our machines will burn up at the mantle and so will we. The layers go: crust, mantle, outer core, inner core.
