Chemistry Test Atomic Structure 4

Question 1

Which of the following sets of quantum numbers (n, l, ml, ms) is NOT valid?

Accepted Answer

(2, 2, 0, +½)

Answer

For n=2, l can only be 0 or 1 (l ranges from 0 to n-1); l=2 is not allowed when n=2.

Question 2

What is the term for the energy required to remove an electron from a gaseous atom in its ground state?

Accepted Answer

Ionization energy

Answer

Ionization energy is the energy needed to remove an electron from a neutral gaseous atom to form a cation.

Question 3

Which model of the atom was replaced by the quantum mechanical model because it could not explain multi-electron atoms?

Accepted Answer

Bohr's planetary model

Answer

Bohr's model worked only for hydrogen; the quantum mechanical model using Schrödinger's equation applies to all atoms.

Question 4

How many orbitals are present in the 4f subshell?

Accepted Answer

7

Answer

The f subshell (l=3) has ml values from -3 to +3, giving 7 orbitals.

Question 5

Carbon-12 and Carbon-14 are isotopes. Which statement accurately compares them?

Accepted Answer

Carbon-14 has 2 more neutrons than Carbon-12

Answer

Both have 6 protons; Carbon-12 has 6 neutrons and Carbon-14 has 8 neutrons — a difference of 2 neutrons.

Chemistry Practice Test