Question

the ground - state electron configuration of sc is
none of the above
1s²2s²2p⁶3s²3p⁹
1s²2s²2p⁶3s²3p⁶3d³
1s²2s²2p⁶3s²3p⁶4s²3d¹
1s²2s²2p⁶3s²3p⁶4s²3d²
question 29
an analysis showed a sample to contain 0.00471 grams of lead. how many micrograms is this?
0.471 μg
4.71×10⁶ μg
4.71×10³ μg
4.71×10² μg
4.71×10⁻⁶ μg

Explanation:

Question 1

Scandium (Sc) has an atomic number of 21. Electrons fill orbitals in the order 1s, 2s, 2p, 3s, 3p, 4s, 3d. The 1s orbital holds 2 electrons, 2s holds 2, 2p holds 6, 3s holds 2, 3p holds 6, 4s holds 2 and then the remaining 1 electron goes to the 3d orbital. So the ground - state electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{1}$.

Step1: Recall the conversion factor

1 gram = $10^{6}$ micrograms.

Step2: Convert grams to micrograms

We have 0.00471 grams. Multiply by the conversion factor: $0.00471\times10^{6}\ \mu g=4.71\times 10^{3}\ \mu g$.

Answer:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{1}$

Question 2