Question

Given the elements Cl, 784 kJ-mol"', match the atoms with their first ionization energies Ge, and K and three values of possible first ionization energies, 418, 1255, a. CI (418), Ge (784), and K (1255 kJ-mol) b. CI (1255), Ge (784), and K (418 kJ-mol) c. CI (784), Ge (1255), and K (418 kJ.mol) d. CI (1255), Ge (418), and K (784 kJ-mol"') e. CI (418), G (1255), and K (784 kJ-mol-)

Answer 1

Answer:

b.  CI (1255 kJ/mol), Ge (784 kJ/mol), and K (418 kJ-mol)

Explanation:

In general, the first ionization energy for a given period increases as we go from left to right in the periodic table (there are some exeptions as with every rule), and the first ionization energy decreases a we go down in the periodic table. The reason for this are:

1. As we move from left to right in a group, the effective nuclear charge increases which makes it harder to remove the electron.

2. As we increase the period in going top to bottom in the periodic table we are adding another shell farther away from the nucleus, making it easier to remove the electron.

Given the three values for the first ionization energy in kJ/mol : 418, 784 and 1255, we expect the highest value to correspond to Cl which belongs to period 3 (K and Ge belong to period 4).

Now comparing K and Ge which belong to period 4, Ge will have a higher effective nuclear charge than K .

So the match will be Cl (1255 kJ/mol), Ge (784) and K(418)

Correct answer is b.

Note: there could be some confusion since the value of 784 was misplaced in the question statement, but we can deduce that in this question we are asked to match the values for the atoms.