A2.00−g sample of a metal x (that is known to form x2+ ions) was added to 0.100 l of 0.500 m h2so4. after all the metal had reacted, the remaining acid required 0.0543 l of 0.500 m naoh solution for neutralization. calculate the molar mass of the metal and identify the element.

87.5 g/mol, Sr (strontium)

Explanation:

The reaction between the metal and the acid is:

X + H₂SO₄ → 2H⁺ + XSO₄ (ion sulfate is SO₄⁻²)

The initial number of moles of the acid is the concentration multiplied by the volume:

n = 0.500*0.1 = 0.05 mol

The reaction between the acid and the base is:

H₂SO₄ + NaOH → NaHSO₄ + H₂O

The number of moles of NaOH is:

0.0543x0.5 = 0.02715 mol

Which is the same number of moles of H₂SO₄, because of the stoichiometry 1:1. So, in the first reaction, reacted:

0.05 - 0.02715 = 0.02285 mol of H₂SO₄

And, for the stoichiometry, there was 0.02285 mol of X. The molar mass of X is the mass divided by the number of moles:

2/0.02285 = 87.5 g/mol

For the periodic table, X is Sr,  strontium.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.