Examples for Chapter 7

Question 1

How many different f orbitals are there?

Answer 1

7

Question 2

What value of ℓ is not allowed for an electron in an n = 3 shell?

Answer 2

3

ℓ can equal any whole integer up to n-1. In this case n = 3, so ℓ can not equal 3.

Question 3

Which combination of n and ℓ is not allowed for an electron in an atom?

Answer 3

n = 1 \quad ℓ = 1

ℓ can never equal n (or be greater than n), because of the rule that ℓ can equal a whole integer up to n-1.

Question 4

Identify the set of quantum numbers that correspond to an electron in an s orbital.

Answer 4

n = 3 \quad ℓ = 0

An s orbital by definition has to have ℓ = 0. When n = 3, this is a 3s orbital.

Question 5

Identify the set of quantum numbers that corresponds to an electron in a p orbital.

Answer 5

n = 4 \quad ℓ = 1

A p orbital by definition has to have ℓ = 1. When n = 4, this is a 4p orbital.

Question 6

Identify the set of quantum numbers that correspond to an electron in a d orbital.

Answer 6

n = 5 \quad ℓ = 2

A d orbital by definition has to have ℓ = 2. When n = 5, this is a 5d orbital.

Question 7

Identify the set of quantum numbers that correspond to an electron in an f orbital.

Answer 7

n= 4 \quad ℓ =3

An f orbital by definition has to have ℓ = 3. When n = 4, this is a 4f orbital.

Question 8

How many d orbitals are there per single value of n (where n ≥ 3) ?

Answer 8

5

A d orbital corresponds to ℓ = 2 which means mℓ = -2, -1, 0, +1, +2. These 5 different values of mℓ give 5 different types of orbitals.
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Question 9

Which set of quantum numbers can represent a 5f orbital?

Answer 9

n=5 \quad ℓ=3 \quad m_ℓ = -2

A 5f orbital has to have n = 5 and ℓ = 3. mℓ = -2 is an allowed value for an f orbital.

Question 10

Which set of quantum numbers can represent a 4d orbital?

Answer 10

n=4 \quad ℓ=2 \quad m_ℓ = -1

A 4d orbital has to have n = 4 and ℓ = 2. mℓ = -1 is an allowed value for a d orbital. mℓ = 3 is not an allowed value for a d orbital.

Question 11

Which quantum number/s are allowed to have negative values?

Answer 11

ml and ms

mℓ = -ℓ, -ℓ+1,… 0… 1-ℓ, ℓ and so can have negative values. m_s = -½ or +½ and so can have one negative value. ℓ = 0…n-1 and so cannot be a negative value.
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Question 12

What is the name of the atom that has a ​[Ne] 3s^23p^5 ground state electron configuration?

Answer 12

Chlorine

A 3p^5 configuration is translated as “5th element in the p block of period 3.”

Question 13

What is the name of the atom that has a ​[Kr] 5s^24d^{10}5p^2 ground state electron configuration?

Answer 13

Tin

A 5p^2 configuration is translated as “2nd element in the p block of period 5.”

Question 14

What is the name of the atom that has a ​[Xe] 6s^24f^9 ground state electron configuration?

Answer 14

Terbium

This element has to be one of the lanthanides. Some lanthanide elements have a 6s^25d^{10}4f^x, while some have only the 6s^24f^x configuration. The lanthanide series starts at lanthanum with the 6s^25d^1 configuration. A 4f^9 configuration is translated as “9th element in the lanthanide series (starting at lanthanum)”. Most periodic tables show cerium as the first element in the f block at the bottom of the periodic table and so starting from cerium this element would then be the 8th box across.

Question 15

What is the charge of the indium ion that has the ​[Kr]4d^{10} electron configuration?

Answer 15

+3

Indium atom has a ​[Kr]5s^{2}4d^{10}5p^1electron configuration. Indium first loses the 5p^1 electron to form In+ and then loses the 5s^2 electrons to form In^{3+} with a [Kr]4d^{10} configuration.

Question 16

Which ion has the largest ionic radius?

Answer 16

K+

Ionic size increases down a group in the same way atomic size increases due to electrons being placed in orbitals farther and farther away from the nucleus. So the biggest will be the one in the lowest period. This narrows it down to K^{+}or Ca^{2+} both of which are isoelectronic, but Ca^{2+} has one extra proton in the nucleus and so this has a stronger pull on the electrons, making K^{+}the largest.

Question 17

Which element has the highest electron affinity?

Answer 17

S

Electron affinity increases towards the top right-hand corner of the periodic table. These are elements that tend to form anions. Sulfur is the element that is located nearest the top right-hand corner and is the only element that tends to form an anion.
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