Correct answer- B the electrons every two elements are arranged in energy levels: a maximum two electrons in the first level. ((( i thinkkk )))
Answer is: Ka for the
monoprotic acid is 3.03·10⁻⁴.
<span>
Chemical reaction: HA(aq) </span>⇄ A⁻(aq) + H⁺<span>(aq).
c(monoprotic acid) = 0.0165 M.
pH = 2.68.
[A</span>⁻] = [H⁺] = 10∧(-2.68).<span>
[A</span>⁻]
= [H⁺] = 0.00209 M; equilibrium concentration.<span>
[HA] = 0.0165 M - 0.00209 M.
[HA] = 0.0144 M.
Ka = [A</span>⁻]·[H⁺] / [HA].<span>
Ka = (0.00209 M)² / 0.0144 M.
Ka = 0.000303 M = 3.03·10</span>⁻⁴<span> M.</span>
Answer:
Iron (Fe)
Explanation:
The number of electrons (-) is usually the same as the number of protons (+) in the atom of the element (unless it is an ion).
The element described has 26 electrons, so we can assume that it has 26 protons as well. The number of protons in an atom is the atomic number of element that the atom is.
Element 26 on the PTE is Iron (Fe), which does rust (oxidation) in air and water.
