Which of the following statements is correct?

a. The greatest probability of finding a #"1s"# electron is at the nucleus.
b. The size of an orbital is directly proportional to its principal quantum number,
c. A #"3p"# orbital can hold three electrons.
d. A #"2s"# orbital is different from a #"1s"# orbital because the #"2s"# orbital requires more energy for the electrons to fill it.

1 Answer
Jan 28, 2017

Answer:

d. #"2s"# is different from #"1s"# because the #"2s"# requires more energy for the electrons to fill it.

Explanation:

a. This option is wrong.

The probability of finding electrons of any orbital in the nucleus is zero.

Here are the probability plots for #"1s, 2s"#, and #"3s"# orbitals.

Probability plots
(From Quora)

Notice that the probability is zero at the nucleus (0 pm).

b. This option is wrong.

The sizes of the orbitals are roughly proportional to #n^2#, where #n# is the principal quantum number.

fc.deltasd.bc.ca

Thus, the #"2s"# orbital is about four times as big as a #"1s"# orbital.

c. This option is wrong.

The Pauli Exclusion Principle states that no orbital can hold more than two electrons.

d. This option is correct.

#"2s"# is different from #"1s"# because the #"2s"# requires more energy for the electrons to fill it.

A #"2s"# orbital is bigger than a #"1s"# orbital, and it takes energy to move an electron further away from the attraction of the nucleus.

Thus, a #"2s"# orbital is higher in energy than a #"1s"# orbital.