Master Electron Configuration Questions for DAT Exam Prep

II. Orbital and Periodicity questions

Electron configuration questions

There are a total of 43 orbital, periodicity, and clectron configuration questions, which are important content-oriented in the summary part of this chapter. Approximately 1 minute is given per question in each test. After the test, if you press the “See Result” button, the results will be displayed along with the answer choices. Red marks indicate incorrect answers and green marks indicate correct answers. Explanations or solutions to the questions are displayed below each question.

ORBITAL AND PERIODICITY TEST 1

1 / 20

Choose the INCORRECT statement about orbital theory.

A. Modern atomic model indicates a high probability of finding certain positioned electrons around the nucleus.

B. The orbital is the path of an electron circling around a nucleus. Unlike a planetary orbit, this path is not fixed.

C. When an electron is transferred from low to high shell, energy is absorbed.

D. The paths of electrons circling around nucleus of a hydrogen atom are described by Bohr’s atomic model.

E. All are correct.

Explanation:

All are correct statements.

2 / 20

When energized “excited” electrons in the outer shell fall down to the n=2 shell, energy is emitted. Which of the following is true for that statement?

A. Lyman series

B. Balmer series

C. Paschen series

D. Infrared region

E. C and D

Explanation:

The Lyman series of the Ultraviolet region emit energy when excited electrons fall down to n=1 shell. The Balmer series of the Visible region emit energy when excited electrons fall down to n=2 shell. The Paschen series of the Infrared region emit energy when excited electrons fall down to the n=3 shell.

3 / 20

Which of the following movements of an excited electron emits the highest energy?

A. N (n=4) → M (n=3)

B. N (n=4) → K (n=1)

C. N (n=4) → L (n=2)

D. K (n=1) → N (n=4)

E. L (n=2) → N (n=4)

Explanation:

The difference of the energy level is K(n=1) < L(n=2) < M(n=3) < N(n=4). To be absorbed the strong energy and become an excited electron, the electron must move from the lowest shell K (n=1), near the nucleus, to higher shells. To emit strong energy, excited electrons must fall from any of the high shells back to the lowest shell K (n=1).

4 / 20

Which of the following is the correct statement about the shapes of orbitals?

A. Dumbbell-shaped p orbitals exist at any electron shell.

B. Spherical shaped s orbitals have three orientations of coordinate axes, Px, Py, or Pz.

C. d orbitals have cloverleaf shapes and appear in the non-metal region of the periodic table.

D. f orbitals have 7 different orbitals and contain 7 electrons total in the orbitals.

E. The electron shell n=3 contains s, p, and d orbitals.

Explanation:

Dumbbell-shaped p orbitals exist at all electron shells except n=1. Spherical shaped s orbitals are spread near nucleus with no direction. Three orientations of coordinate axes, P_x, P_y, or P_z, are features of p orbitals. Cloverleaf-shaped d orbitals appear in the transition metal region of the periodic table. Each orbital holds a maximum of 2 electrons; therefore 7 different f orbitals contain 14 electrons.

5 / 20

Which of the following does NOT describe how electrons fill orbitals?

A. Each orbital can hold one or two electrons.

B. The 3d orbital has a higher energy level than the 4s orbital.

C. Electrons in each orbital spin in opposite directions.

D. The electrons are filled into orbitals from high energy level to low energy level.

E. Electrons are half-filled into each orbital and then fully filled.

Explanation:

The electrons are filled into orbitals from low energy level to high energy level. 1s<2s<2p<3s<3p<4s<3d<4d …

6 / 20

Which of the following is the most important indicator of the energy level of an orbital?

A. Principal quantum number (n)

B. Angular momentum quantum number (l)

C. Magnetic quantum number (m_l)

D. 3-D shape of the orbital

E. Spin quantum number (m_s)

Explanation:

The principal quantum number, n, represents the position of shells, the number of orbital types, and the energy level of orbitals. The angular momentum quantum number, l, indicates a 3d shape of the orbital. The magnetic quantum number, m_l, indicates orbital axes of spatial orientation. The spin quantum number, m_s, indicates the direction of spins.

7 / 20

Which of the following is a possible configuration for quantum numbers?

A. n=1, l=1, m_l =0

B. n=2, l=1, m_l =+2

C. n=2, l=3, m_l =+3

D. n=3, l=2, m_l =-2

E. n=4, l=4, m_l =-1

Explanation:

8 / 20

One shell can hold a maximum of 32 electrons. This principal quantum number is _______________.

A. n=1

B. n=2

C. n=3

D. n=4

E. n=5

Solution:

The principal quantum number of n=4 contains a total of 16 (1+3+5+7) orbitals. Each orbital can hold a maximum of 2 electrons. Therefore, 16 × 2 =32 maximum electrons can be held in n=4. (Maximum number of electrons in shell: 2n² → 2n² = 32, n=4)

9 / 20

Which of the following is a possible quantum number when orbital notation is 4d?

A. n=2, l=1

B. n=3, l=3

C. n=3, l=2

D. n=4, l=3

E. n=4, l=2

Explanation:

10 / 20

Which of the following could be the lowest principal quantum number to be involved in a d orbital?

A. 1

B. 2

C. 3

D. 4

E. 5

Explanation:

The principal quantum number of n=1 has only s orbital and the principal quantum number of n=2 has s and p orbital. From the principal quantum number of n=3, d orbital begins to be involved.

11 / 20

Which of the following is an INCORRECT statement?

A. The total number of orbitals in the second shell is 3.

B. The third shell (n=3) can hold maximum 18electrons.

C. The principal quantum number of n=4 has four types of orbitals, s, p, d and f.

D. Angular-momentum quantum number, l, expresses the 3-D shape of the orbital.

E. The magnetic quantum number, M_l, expresses the spatial orientation of the orbital coordinate axes.

Solution:

12 / 20

Choose the orbital with the highest energy.

A. 3d

B. 4s

C. 3s

D. 3p

E. 2p

Solution:

From the lower to higher energy in orbitals:

1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → ….

13 / 20

Which of the following atoms can belong to the 3p orbital?

A. Mg

B. Al

C. Li

D. O

E. Fe

Explanation:

Al, Si, P, S, Cl, and Ar belong to the 3p orbital in the periodic table.

14 / 20

Which of the following is correct for the ground state electron configuration of the atoms?

A. K⁺: [Ne]3s²3P⁵4S¹

B. Ti²⁺ : [Ar]4S²

C. Br^–: [Ar]4s²3d¹⁰4p⁵

D. N^3- : [He]2s²2P⁵3S¹

E. V²⁺: [Ar]3d³

explanation:

Natural atoms	Ionic atoms

15 / 20

Which of the following pairs has the same number of unpaired electrons in orbitals when they are the ground state?

A. Boron, oxygen

B. Phosphorus, argon

C. Titanium, nickel

D. Sodium, magnesium

E. Titanium, cobalt

explanation:

16 / 20

Which of the following is the INCORRECT statement about the electron configuration of [Ar]4s²3d¹?

A. This atom is Scandium.

B. [Ar]4s¹3d² could be said to be the excited state of this atom.

C. There are 8 electrons at l=0 of angular momentum quantum number.

D. There is only 1 unpaired electron.

E. There is only 1 outermost electron.

Solution:

The electro configuration of Sc is 1s²2s²2p⁶3s²3p⁶4s²3d¹. The orbitals, which are l=0 of angular momentum quantum number, are 1s, 2s, 3s, and 4s. Therefore, the total electrons in 1s, 2s, 3s, and 4s orbitals are 4 ×2 = 8. There are 2 outermost electrons contained in 4s orbital.

17 / 20

How many orbitals for silicon are filled by electrons at ground state?

A. 7

B. 8

C. 9

D. 14

E. 16

Solution:

The ground state electro configuration of silicon is 1s²2s²2p⁶3s²3p². 1s² = 1 orbital, 2s² = 1 orbital, 2p³ = 3 orbitals, 3s² = 1 orbital, 3p² containing 2 electrons = 2 orbitals. Therefore, the total number of orbitals filled by electrons is 1+1+3+1+2 = 8.

18 / 20

Below is a orbital-filling diagram of unknown atoms. Which of the following is an INCORRECT statement?

A. II is an excited state atom.

B. When I becomes II, energy is emitted.

C. I and II are the same atoms.

D. The atomic radius of III is smaller than the atomic radius of I.

E. The atom of the smallest unpaired electrons is III.

Explanation:

I is the ground state atom and II is the excited state of P atom. When the ground state atom becomes the excited state atom, energy is absorbed. III is Cl atom. Therefore, atomic radius is P > Cl. I and II have 3 unpaired electrons and III has 1 unpaired electron.

19 / 20

Which of the following apply to the ground state selenium.

I. Se^2- = [Kr]

II. Having 4d orbitals.

III. 2 vacancy electron at p orbitals.

IV. l=1 of angular momentum quantum number is 4p orbitals.

A. I only

B. I and II

C. I and III

D. I, III, and IV

E. All apply

Explanation:

20 / 20

How many are fully-filled orbitals for fluorine?

A. 1

B. 2

C. 4

D. 5

E. 8

Explanation:

Your score is

The average score is 25%

ORBITAL AND PERIODICITY TEST 2

1 / 20

Which of the following radiations is the highest frequency of a photon?

A. Radio waves

B. Microwaves

C. Gamma rays

D. Ultraviolet light

E. Visible light

Explanation:

E = hν

The higher frequency (ν), the higher energy (E). The order of energy from lower to higher:

Radio waves < Microwaves < Infrared light < Visible light < Ultraviolet light< X rays < Gamma rays

2 / 20

Which of the following is INCORRECT?

A. High energy has short wavelength.

B. High frequency has short wavelength.

C. Low energy has low frequency.

D. The wavelength of visible light is longer than radio waves.

E. Usually all types of light have the same speed.

Explanation:

3 / 20

Which of the following does NOT apply to metal?

A. Easy oxidized

B. Brittle

C. Ductile

D. Malleable

E. Characterized by luster and shine

Explanation:

Metal: easy oxidation (reducing agent), malleability, ductility, shiny luster, and good conductivity for heat and electricity.

Nonmetal: easy reduction (oxidizing agents), brittleness, and poor conductivity for heat and electricity.

4 / 20

Which of the following is true for atoms in the periodic table?

A. In the same group atoms have the same number of shells.

B. Alkali metal group has a high electro affinity.

C. Atoms in the same period have similar chemical properties.

D. The halogen group is a strong reducing agent.

E. Alkaline earth metals have two electrons in their outermost shell.

Explanation:

In the same periods, atoms have the same number of shells. Halogen group has a higher electro affinity. In the same group, atoms have similar chemical properties because of the same outermost electrons (valence electrons). Alkali metal group is the strong reducing agents and halogen group is the strong oxidizing agents.

5 / 20

Which of the following is an INCORRECT example for the atom of each group?

A. Alkali metal = H

B. Transitional metal = Zn

C. Halogen = I

D. Noble gas = Kr

E. Alkali earth metal = Ba

Explanation:

Hydrogen, H, does not belong to metal group. It belongs to a non-metal group.

6 / 20

Which of the following has chemical property similar to chlorine?

A. Sulfur

B. Oxygen

C. Fluorine

D. Argon

E. Magnesium

Explanation:

Atoms positioned in the same groups have similar chemical properties. Fluorine and chlorine belong to the same 7A group.

7 / 20

Which of the following has intermediate chemical properties between metals and nonmetals?

A. Ga

B. Al

C. Ge

D. Sn

E. Se

Explanation:

The elements that have intermediate chemical properties between metals and nonmetals, are called semimetal or metalloids. B, Si, Ge, As, Sb, Te, and At belong to this semimetal group. Ga, Al, and Sn are metals, and Se is a nonmetal.

8 / 20

Choose the phrases that apply to the 7A group.

I. Nonmetals except astatine.

II. Paramagnetic.

III. Act as Lewis base when it is an ion.

IV. Forming cations.

A. I only

B. I and III

C. I and IV

D. II and IV

E. I, II, and III

Explanation:

Atoms of the 7A group are halogens, which are nonmetals (except astatine), acting as Lewis base when it is forming (–1) anions (**see the acid and base theory in Ch IX). Paramagnetic and forming cations are metals.

9 / 20

Choose the phrases that apply to the transition metals.

I. Have d orbitals.

II. Paramagnetic.

III. Calcium and cobalt.

IV. Multiple oxidation states.

A. I only

B. I and II

C. II and III

D. II and IV

E. I, II, and IV

Explanation:

Transition metals, between 2A and 3A group, contain d orbitals and are paramagnetic.

Calcium is belongs to the alkali earth metals.

Transition metals form multiple oxidation states.

10 / 20

Which of the following has the largest atomic radius?

A. Nitrogen

B. Oxygen

C. Fluorine

D. Phosphorus

E. Sulfur

Explanation:

In the periodic table, going in the direction left and down, the radius of atoms becomes bigger.

Phosphorus is positioned at the far left and down in the period table among the atoms.

11 / 20

Which of the following is correct pair for the comparison of the atomic radius?

A. Rb⁺ < Rb, Br^– < Br

B. Rb⁺ > Rb, Br^– < Br

C. Rb⁺ > Rb, Br^– > Br

D. Rb⁺ < Rb, Br^– > Br

E. Rb⁺ = Rb, Br^– = Br

Explanation:

The radius of a cation is smaller than its natural atom because the number of shells is decreased. The radius of an anion is bigger than its natural atom because the increasing repulsion between electrons causes an increase in the anionic radius.

12 / 20

There are five isoelectronics, O^2-, F^–, Ne, Na⁺, and Mg²⁺. Choose the correct order from smaller to larger atomic radius.

A. O^2- < F^–< Ne < Na⁺ < Mg²⁺

B. Mg²⁺< Na⁺< Ne< F^–< O^2-

C. Ne < F^–< O^2-< Mg²⁺< Na⁺

D. O^2-<F^–<Ne < Na⁺ < Mg²⁺

E. Ne = F^–= O^2-= Mg²⁺= Na⁺

Explanation:

The size of radius between isoelectronic elements: bigger cations < natural atoms < bigger anions

13 / 20

Which of the following is the largest second ionization energy to get rid of its outmost electron?

A. [Ne]3s²3P³

B. [Ne]3s²3P⁵

C. [Ar]

D. [Ar]4s¹

E. [Ar]4s²

Explanation:

The atom with fully-filled electrons in orbitals has strong first ionization energy ([Ar]). The atom with 1 outermost electron has strong second ionization energy ([Ar]4s¹). The atom with 2 outer most electrons has strong third ionization energy ([Ar]4s²).

14 / 20

Of the following, which is the correct order of the first ionization energy to remove its outmost electron(s) from higher to lower?

N, O, F, Ne, Na

A. Na > Ne > F > O > N

B. Ne > F > N > O > Na

C. N > O > F > Ne > Na

D. Na > F > O > N > Ne

E. Ne > F > O > N > Na

Explanation:

In the same period with the increasing atomic number, the E_i is increased. In the same group with the increasing atomic number, the E_i is decreased. The half-filled or fully-filled electron(s) in each orbitals have a strong E_i,such as N > O or Ne > F.

15 / 20

The following chart indicates the ionization energy (Kcal/mol) of atoms. Which of the following could be the X group?

A. Alkali metals

B. Alkali earth metals

C. Transition metals

D. Halogens

E. Noble gases

Explanation:

The chart shows the high gap of ionization energy between E2 and E3, indicating that this group has strong E3 (third ionization energy). Atoms containing 2 outmost electrons (alkali earth metals) have strong E3.

16 / 20

Which of the following electro configurations has the lowest electron affinity?

A. 1s²2s¹

B. 1s²2s²2p¹

C. 1s²2s²2p²

D. 1s²2s²2p³

E. 1s²2s²2p⁴

Explanation:

In the same period, with increasing atomic numbers, the E_ea is increased. An atom that emits one electron from half-filled or fully-filled orbitals has a strong E_ea such as 1s²2s²2p² or 1s²2s²2p⁵, but an atom that has half-filled or fully-filled electron(s) at orbitals has a weak E_ea such as 1s²2s²2p³or 1s²2s²2p⁶.

17 / 20

Which of the following has the highest electron affinity?

A. O

B. O^2-

C. F

D. F^–

E. Ne

Explanation:

Electron affinitive (E_ea) means negative (emitting) energy when an atom accepts an electron and become an anionic atom. The fluorine atom, F, has 7 electrons at the outermost orbital. This atom has the strong affinity to accept 1 electron for becoming a stable ionic atom, which will have 8 electrons at the outermost orbital.

18 / 20

Of the following, which is the correct order for electron affinity from lower to higher?

A. Si < P < S < Cl

B. P < Si < S < Cl

C. P < S < Si < Cl

D. Si < Cl < P < S

E. Si < P < Cl < S

Explanation:

In the same period, with the increasing atomic number, the E_ea is increased. In the same group, with the increasing atomic number, the E_ea is decreased. An atom that emits one electron from half-filled or full-filled orbitals, have a strong E_ea such as Si > P or Cl > Ar.

19 / 20

Which of the following represents, in order, the strongest electron affinitive, smallest radius, and the highest first ionization energy from the three atoms shown here?

He, F, Ne

A. F, He, He

B. F, F, He

C. He, F, He

D. Ne, Ne, F

E. F, Ne, Ne

Explanation:

The halogen group usually has strong electron affinitive because the atoms of 7 outermost electrons want to attract 1 electron to be in a stable state. Going in the direction left and down on the periodic table, the atomic radius becomes bigger. Noble gases have strong first ionization energy because of the stable 8 outermost electrons. The attraction between nucleus (+ charge) and electrons (-charge) is increased with the close distance between them. Therefore, He has higher first ionization energy than Ne.

20 / 20

Which of the following has the weakest electronegativity?

A. F

B. O

C. N

D. S

E. P

Explanation:

Electronegativity is decreased going in the direction left and down in the period table.

Your score is

The average score is 15%

ORBITAL AND PERIODICITY TEST 3

1 / 3

In the periodic table, the following is true going in the direction left and down.

A. London dispersion is increased.

B. Atomic radius is decreased.

C. Electronegativity is increased.

D. Metallic character is decreased.

E. Ionization energy is increased.

Explanation:

London dispersion is the forces of electron motions in atoms or molecules. London dispersion forces increase with the size of atoms or molecules. Atomic size and London dispersion forces are increased when going in the direction left and down in the periodic table.

2 / 3

Atomic radius, London dispersion force, and metallic character are increased in the direction left and down in the period table. In the same direction, ionization energy, electro affinity, and electronegative are decreased.

I. Sc < Ca < Sr < Ba

II. Te < Se < S < Cl

A. I: Electron affinity, II: Electronegativity

B. I: Metallic properties, II: Intermolecular forces

C. I: Atomic radius, II: Electron Affinity

D. I: Ionization energy, II: Intermolecular forces

E. I: Ionization energy, II: Atomic radius

Explanation:

3 / 3

Which of the following is the INCORRECT statement?

A. Within a group, the metallic character is increased with the increasing atomic number.

B. The radius of natural metallic atoms is usually larger than its cationic radius.

C. In the same period the radius of atoms is decreased with the increasing atomic number.

D. In the same period the atomic density is increased with the increasing atomic number.

E. All are correct.

Explanation:

All are correct statements. In the same period the atomic radius is decreased and atomic density is increased with the increasing atomic number because increasing number of protons and electrons causes an increase in the attraction between themselves.

Your score is

The average score is 19%

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