Answer :
(1) The electron configuration for the chloride ion will be,
[tex]1s^22s^22p^63s^23p^6[/tex]
(2) The percent by mass of hydrogen in aspirin, [tex]C_9H_8O_4[/tex] is, 4.44%
Explanation for Part 1 :
Element = chlorine
Atomic number = 17
As we know that the number of electrons is equal to the atomic number.
So, the number of electrons = 17
An electronic configuration of neutral chlorine element is,
[tex]1s^22s^22p^63s^23p^5[/tex]
The chloride ion formed by the addition of an electron in chlorine element.
So, the electron configuration for the chloride ion will be,
[tex]1s^22s^22p^63s^23p^6[/tex]
Explanation for Part 2 :
Mass of carbon = 12 g/mole
Mass of hydrogen = 1 g/mole
Mass of oxygen = 16 g/mole
The given compound is aspirin, [tex]C_9H_8O_4[/tex]
The molar mass of aspirin, [tex]C_9H_8O_4[/tex] = 9(12) + 8(1) + 4(16) = 180 g/mole
In the given compound, there are 9 atoms of carbon, 8 atoms of hydrogen and 4 atoms of oxygen.
The mass of hydrogen in aspirin = 8 g/mole
Now we have to calculate the percent mass of hydrogen in aspirin.
[tex]\%\text{ by mass of hydrogen}=\frac{\text{Mass of hydrogen}}{\text{Mass of aspirin}}\times 100=\frac{8}{180}\times 100=4.44\%[/tex]
Therefore, the percent by mass of hydrogen in aspirin, [tex]C_9H_8O_4[/tex] is, 4.44%
