Question

question 30 (0.0862 points)
what is the electron configuration of ge?
kr4s²4d¹⁰4p²
kr4s²3d¹⁰4p²
ar4s²4d¹⁰4p²
ar4s²3d¹⁰4p²
question 31 (0.0862 points)
what is the mass percent of an ammonium carbonate solution prepared by di
30.1 g of solid into 39.5 g of water?
76.2%
30.1%
43.2%
56.8%

Explanation:

Question 30

Step1: Determine Ge's atomic number

Germanium (Ge) has an atomic number of 32. The noble gas before Ge is Argon (Ar, atomic number 18) or Krypton (Kr, atomic number 36). Since 32 < 36, we use Ar as the core.

Step2: Fill orbitals

After Ar (\(1s^2 2s^2 2p^6 3s^2 3p^6\)), we fill \(4s^2\), then \(3d^{10}\) (d orbitals fill after s but before p in the same principal quantum number? No, \(3d\) is n=3, \(4s\) is n=4, but \(4s\) fills before \(3d\), then \(3d\) fills, then \(4p\). So the electron configuration build - up: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^2\). In noble - gas notation, using Ar (\([Ar]=1s^2 2s^2 2p^6 3s^2 3p^6\)), we get \([Ar]4s^2 3d^{10} 4p^2\). Let's check the options:

• Option 1: \([Kr]4s^2 4d^{10} 4p^2\): Kr has atomic number 36, Ge has 32, so this is wrong.
• Option 2: \([Kr]4s^2 3d^{10} 4p^2\): Kr is 36, Ge is 32, wrong.
• Option 3: \([Ar]4s^2 4d^{10} 4p^2\): \(4d\) orbitals fill after \(4p\) in the 4th period? No, \(3d\) fills before \(4p\), and \(4d\) is for higher periods. Wrong.
• Option 4: \([Ar]4s^2 3d^{10} 4p^2\): Correct as per the above reasoning.

Step1: Recall mass percent formula

The formula for mass percent of a solute in a solution is \(\text{Mass percent}=\frac{\text{Mass of solute}}{\text{Mass of solute}+\text{Mass of solvent}}\times100\%\)

Step2: Identify values

Mass of solute (ammonium carbonate) \(m_{solute}=30.1\space g\), mass of solvent (water) \(m_{solvent}=39.5\space g\)

Step3: Calculate total mass of solution

\(m_{solution}=m_{solute}+m_{solvent}=30.1 + 39.5=69.6\space g\)

Step4: Calculate mass percent

\(\text{Mass percent}=\frac{30.1}{69.6}\times100\%\approx43.2\%\)

Answer:

D. \([Ar]4s^2 3d^{10} 4p^2\) (assuming the options are labeled A, B, C, D in order as given)

Question 31