Answer:C) the measurement is close to the accepted value and can be reproduced.
The total number of protons and neutrons in an atom is called the mass number. You can find the mass numberfor any element. The mass number canbe found by rounding the average atomic mass to the nearest whole number.
as an example
6.25 is closer to 6 than 7 so it is 6
6. 50 is closer to 7 so it is 7
you have to look at the thenth digit. if the number is 4 or less you have to round it down
if the tenth digit is 5 or greather than you have to round it up.
As mentioned above, phosphoric acid has 3 pKa values, and after 3 ionization it gives 3 types of ions at different pKa values:
H₃PO₄(aq)
+ H₂O(l) ⇌ H₃O⁺(aq) + H₂PO₄⁻ (aq) pKₐ₁
<span>
</span>H₂PO₄⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HPO₄²⁻ (aq) pKₐ₂
HPO₄²⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + PO₄³⁻ (aq) pKₐ₃
At the highest pKa value (12.4) of phosphoric acid, the last OH group will lose its hydrogen. On the picture I attached, it is shown required protonated form of phosphoric acid before reaction whose pKa value is 12.4.
According to the octet rule, atoms tend to gain, lose, or share electrons until they are surrounded by__8__ valence electrons.