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Chemistry · EUEE topic

Atomic structure and the periodic table: every EUEE question 2015–2017 E.C. (26 questions), solved

26 questions · 2015 ×6 · 2016 ×9 · 2017 ×11

Atomic models, isotopes, electron configuration and periodic trends from EUEE Chemistry.

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2015 E.C.

2015 E.C. · natural · Q4 · Chemical bonding / molecular orbital

Which one of the following resulted from interaction of the atomic orbitals of bonding atoms to produce new electron distribution associated with the entire molecule?
  1. A. Hybrid orbital
  2. B. Molecular orbital
  3. C. Electron orbit
  4. D. Bohr orbit
Worked solutionUnofficial

Answer: B

Answer B: Molecular orbital. The stem is: Which one of the following resulted from interaction of the atomic orbitals of bonding atoms to produce new electron distribution associated with the entire molecule? Letter B is the Abrari key for this Chemical bonding / molecular orbital.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2015 E.C. · natural · Q21 · Atomic structure / isotopes

Which one of the following IS TRUE about isotopes?
  1. A. Isotopes of an element are atoms that have different number of electrons and protons.
  2. B. Isotopes of an element are identical in mass number.
  3. C. Isotopes of the same elements contain the same number of neutrons.
  4. D. Isotopes of an element have the same chemical properties.
Worked solutionUnofficial

Answer: D

Answer D: Isotopes of an element have the same chemical properties.. The stem is: Which one of the following IS TRUE about isotopes? Letter D is the Abrari key for this Atomic structure / isotopes.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2015 E.C. · natural · Q23 · Atomic structure / notation

Which one of the following is the diagrammatic representation of 1735Cl^{35}_{17}Cl (chlorine-35)?

This item uses a figure in the original paper (not redrawn here).

  1. A. [atom diagram]
  2. B. [atom diagram]
  3. C. [atom diagram]
  4. D. [atom diagram]
Worked solutionUnofficial

No keyed letter is published for this item. No keyed letter is published for this 2015 E.C. natural item (Atomic structure / notation). Answer depends on diagram images showing 17 protons, 18 neutrons, 17 electrons; correct option cannot be identified without viewing images.Try the options yourself, then practise the same subject timed in the app.

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2015 E.C. · natural · Q25 · Periodic properties

An element is located in Group VIIA and 3rd period of the modern periodic table. On the basis of this the element:
  1. A. generally forms an ion with -2 charges.
  2. B. has very low ionization energy.
  3. C. forms an acidic oxide.
  4. D. has extremely low electron affinity.
Worked solutionUnofficial

Answer: C

Answer C: forms an acidic oxide.. The stem is: An element is located in Group VIIA and 3rd period of the modern periodic table. On the basis of this the element: Letter C is the Abrari key for this Periodic properties.

Unofficial — solved by Abrari, not an official EAES key.

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2015 E.C. · natural · Q50 · Metallic bonding model

In order to illustrate the structure and properties of a solid, a student put hundred marble balls in to a box that representing metal cations and the empty space between and around the marble representing the electron sea. Which one of the following bonding is represented by this model?
  1. A. Covalent bonding
  2. B. Ionic bonding
  3. C. Metallic bonding
  4. D. Dative bonding
Worked solutionUnofficial

Answer: C

Answer C: Metallic bonding. The stem is: In order to illustrate the structure and properties of a solid, a student put hundred marble balls in to a box that representing metal cations and the empty space between and around the marble representing the electron sea. Which one of the following bonding is represented by th… Letter C is the Abrari key for this Metallic bonding model.

Unofficial — solved by Abrari, not an official EAES key.

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2015 E.C. · natural · Q54 · Quantum numbers

What are the four quantum numbers for an electron in a 2s orbital?
  1. A. 2, 1, 0, + 1/2
  2. B. 2, 1, 1, + 1/2
  3. C. 2, 0, 0, + 1/2
  4. D. 2, 0, 1, + 1/2
Worked solutionUnofficial

Answer: C

Answer C: 2, 0, 0, + 1/2. The stem is: What are the four quantum numbers for an electron in a 2s orbital? Letter C is the Abrari key for this Quantum numbers.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C.

2016 E.C. · natural · Q8 · Lewis structures

Which of the following is the CORRECT Lewis electron-dot symbol of MgO? (Atomic number: Mg = 12 and O = 8)
  1. A. Mg+ and O 2- (dots)
  2. B. Mg+2 and O - (dots)
  3. C. Mg+ and O - (dots)
  4. D. Mg+2 and O 2- (dots)
Worked solutionUnofficial

Answer: D

Answer D: Mg+2 and O 2- (dots). The stem is: Which of the following is the CORRECT Lewis electron-dot symbol of MgO? (Atomic number: Mg = 12 and O = 8) Letter D is the Abrari key for this Lewis structures. MgO is ionic: Mg2+ and O2-.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q19 · Molecular orbital theory

Which of the following is the CORRECT electron configuration of a peroxide ion, O2 2-?
  1. A. (s1s)2(s*1s)2(s2s)2(s*2s)2(s2px)2(pi2py2=pi2pz2)(pi*2py=pi*2pz)2(s*2z)2
  2. B. (s1s)2(s*1s)2(s2s)2(s*2s)2(s2px)2(pi2py2=pi2pz2)(pi*2py=pi*2pz)2(s*2z)
  3. C. (s1s)2(s*1s)2(s2s)2(s*2s)2(s2px)2(pi2py2=pi2pz2)(pi*2py=pi*2pz)2(s*2z)2
  4. D. (s1s)2(s*1s)2(s2s)2(s*2s)2(s2px)2(pi2py2=pi2pz2)(pi*2py=pi*2pz)2(s*2z)
Worked solutionUnofficial

Answer: A

Answer A: (s1s)2(s*1s)2(s2s)2(s*2s)2(s2px)2(pi2py2=pi2pz2)(pi*2py=pi*2pz)2(s*2z)2. The stem is: Which of the following is the CORRECT electron configuration of a peroxide ion, O2 2-? Letter A is the Abrari key for this Molecular orbital theory. Peroxide ion O2(2-) has 18 electrons with fully filled antibonding pi orbitals. Choices A and C appear identical as transcribed; source MO notation is corrupted/ambiguous.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q31 · Periodic table blocks

The electronic configuration of an element is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5. In which block does this element belong?
  1. A. f-block
  2. B. d-block
  3. C. p-block
  4. D. s-block
Worked solutionUnofficial

Answer: C

Answer C: p-block. The stem is: The electronic configuration of an element is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5. In which block does this element belong? Letter C is the Abrari key for this Periodic table blocks. Highest energy electron in 4p; p-block.

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q32 · Periodic trends

From the given periodic properties chart, which one CORRECTLY agrees with the periodic trend in the chart?

This item uses a figure in the original paper (not redrawn here).

  1. A. Electronegativity
  2. B. Electron affinity
  3. C. Ionization energy
  4. D. Atomic radius
Worked solutionUnofficial

No keyed letter is published for this item. No keyed letter is published for this 2016 E.C. natural item (Periodic trends). Answer depends on the arrow direction shown in the chart image.Try the options yourself, then practise the same subject timed in the app.

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2016 E.C. · natural · Q38 · Subatomic particles

Which of the following is the CORRECT comparison of the absolute masses of protons, electrons and neutrons?
  1. A. Mass of e- > mass of p+ = mass of n0
  2. B. Mass of e- = mass of p+ > mass of n0
  3. C. Mass of e- < mass of p+ < mass of n0
  4. D. Mass of e- > mass of p+ > mass of n0
Worked solutionUnofficial

Answer: C

Answer C: Mass of e- < mass of p+ < mass of n0. The stem is: Which of the following is the CORRECT comparison of the absolute masses of protons, electrons and neutrons? Letter C is the Abrari key for this Subatomic particles. Electron < proton < neutron mass.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q39 · Periodic groups

In the modern periodic table, what is the name of the group that contains the most electronegative elements?
  1. A. Alkali
  2. B. Halogens
  3. C. Chalcogens
  4. D. Noble gases
Worked solutionUnofficial

Answer: B

Answer B: Halogens. The stem is: In the modern periodic table, what is the name of the group that contains the most electronegative elements? Letter B is the Abrari key for this Periodic groups.

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q40 · Metallic character

A given element has atomic number of 55 and mass number of 133. Which of the following describes CORRECTLY the property of this element?
  1. A. The non-metallic character of the element is high.
  2. B. The metallic character of the element is high.
  3. C. The element has high electron affinity.
  4. D. The element has high electronegativity.
Worked solutionUnofficial

Answer: B

Answer B: The metallic character of the element is high.. The stem is: A given element has atomic number of 55 and mass number of 133. Which of the following describes CORRECTLY the property of this element? Letter B is the Abrari key for this Metallic character. Element is Cs (Z=55), an alkali metal.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q48 · Bohr's theory

'The hydrogen atom moves in a fixed circular orbit associated with allowable energy states' This is called ____.
  1. A. Planck's theory
  2. B. Bohr's theory
  3. C. Pauli's principle
  4. D. Aufbau's principle
Worked solutionUnofficial

Answer: B

Answer B: Bohr's theory. The stem is: 'The hydrogen atom moves in a fixed circular orbit associated with allowable energy states' This is called ____. Letter B is the Abrari key for this Bohr's theory.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2016 E.C. · natural · Q49 · Electron configuration of ions

Which of the following is the core electron configuration of the metal ion in ferric sulfate, Fe2(SO4)3? (Atomic Number of Fe = 26)
  1. A. [Ar]4s23d6
  2. B. [Ar]4s13d6
  3. C. [Ar]3d6
  4. D. [Ar]3d5
Worked solutionUnofficial

Answer: D

Answer D: [Ar]3d5. The stem is: Which of the following is the core electron configuration of the metal ion in ferric sulfate, Fe2(SO4)3? (Atomic Number of Fe = 26) Letter D is the Abrari key for this Electron configuration of ions. Fe3+ = [Ar]3d5.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C.

2017 E.C. · natural · Q6 · Molecular orbital theory

What is the electron configuration of O2−O_2^- molecule as per the molecular orbital model? (Atomic number of O=8O = 8)
  1. A. σ₁s² σ₁s*² σ₂s² σ₂s*² σ₂px² (π₂py² = π₂pz²) (π*₂py¹ = π*₂pz¹)
  2. B. σ₁s² σ₁s*² σ₂s² σ₂s*² σ₂px² (π₂py² = π₂pz²) (π*₂pz²)
  3. C. σ₁s² σ₁s*² σ₂s² σ₂s*² σ₂px² (π₂py² = π₂pz²) (π*₂py² = π*₂pz²)
  4. D. σ₁s² σ₁s*² σ₂s² σ₂s*² σ₂px² (π₂py² = π₂pz²) (π*₂py² = π*₂pz¹)
Worked solutionUnofficial

Answer: D

Answer D: σ₁s² σ₁s*² σ₂s² σ₂s*² σ₂px² (π₂py² = π₂pz²) (π*₂py² = π*₂pz¹). The stem is: What is the electron configuration of O2−O_2^- molecule as per the molecular orbital model? (Atomic number of O=8O = 8) Letter D is the Abrari key for this Molecular orbital theory. O2- has 17 electrons; correct config ends (π*₂py² = π*₂pz¹) = choice D. Site says A, but A has only 16 electrons (neutral O2). Disagree with site; multiple commenters also say D.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q8 · Atomic structure / EM radiation

A mineral absorbs purple light of frequency 7.11×1014 Hz7.11 \times 10^{14}\ \text{Hz}. What is the wavelength (in nm) of the absorbed light? (c=3.00×108 m/sc = 3.00 \times 10^8\ \text{m/s})
  1. A. 314.5 nm
  2. B. 421.9 nm
  3. C. 237.5 nm
  4. D. 184.4 nm
Worked solutionUnofficial

Answer: B

Answer B: 421.9 nm. The stem is: A mineral absorbs purple light of frequency 7.11×1014 Hz7.11 \times 10^{14}\ \text{Hz}. What is the wavelength (in nm) of the absorbed light? (c=3.00×108 m/sc = 3.00 \times 10^8\ \text{m/s}) Letter B is the Abrari key for this Atomic structure / EM radiation. λ = c/f = 3.00e8 / 7.11e14 = 4.219e-7 m = 421.9 nm.

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q9 · Atomic structure / energy transitions

Why do atoms absorb energy when their electrons undergo transitions from a lower energy to a higher energy level? This is because
  1. A. The electrons of the atoms absorb energy when they go from higher to lower energy.
  2. B. The electrons of the atoms do not have allowable energy levels.
  3. C. The electrons of the atoms move from one orbit of higher radius to another one having lower radius.
  4. D. The electrons of the atoms move from one orbit of lower radius to another one having larger radius.
Worked solutionUnofficial

Answer: D

Answer D: The electrons of the atoms move from one orbit of lower radius to another one having larger radius.. The stem is: Why do atoms absorb energy when their electrons undergo transitions from a lower energy to a higher energy level? This is because Letter D is the Abrari key for this Atomic structure / energy transitions.

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q10 · Quantum numbers

What are the quantum numbers for the 5s orbital?
  1. A. n=5, l=0, ml=0, ms=±12n=5,\ l=0,\ m_l=0,\ m_s=\pm\frac{1}{2}
  2. B. n=5, l=2, ml=−2, ms=±12n=5,\ l=2,\ m_l=-2,\ m_s=\pm\frac{1}{2}
  3. C. n=5, l=1, ml=−2, ms=±12n=5,\ l=1,\ m_l=-2,\ m_s=\pm\frac{1}{2}
  4. D. n=5, l=0, ml=−1, ms=±12n=5,\ l=0,\ m_l=-1,\ m_s=\pm\frac{1}{2}
Worked solutionUnofficial

Answer: A

Answer A: n=5, l=0, ml=0, ms=±12n=5,\ l=0,\ m_l=0,\ m_s=\pm\frac{1}{2}. The stem is: What are the quantum numbers for the 5s orbital? Letter A is the Abrari key for this Quantum numbers.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q11 · Quantum numbers / Pauli

Which of the following is CORRECT about the set of quantum numbers assigned to the two electrons of the helium atom?
  1. A. The magnetic quantum numbers of both electrons are different.
  2. B. The second electron occupies the same orbital as the first with the opposite spin quantum number.
  3. C. The second electron occupies the same orbital as the first with the same spin quantum number.
  4. D. Both electrons have the same four quantum numbers.
Worked solutionUnofficial

Answer: B

Answer B: The second electron occupies the same orbital as the first with the opposite spin quantum number.. The stem is: Which of the following is CORRECT about the set of quantum numbers assigned to the two electrons of the helium atom? Letter B is the Abrari key for this Quantum numbers / Pauli.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q28 · Isotopes / average atomic mass

Silver has two known isotopes, 107^{107}Ag and 108^{108}Ag with their percent abundance of 52% and 48%, respectively. What is the average atomic mass of silver?
  1. A. 108.86
  2. B. 107.48
  3. C. 108.06
  4. D. 107.89
Worked solutionUnofficial

Answer: B

Answer B: 107.48. The stem is: Silver has two known isotopes, 107^{107}Ag and 108^{108}Ag with their percent abundance of 52% and 48%, respectively. What is the average atomic mass of silver? Letter B is the Abrari key for this Isotopes / average atomic mass. 107*0.52 + 108*0.48 = 55.64 + 51.84 = 107.48.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q38 · Hybridization / BeCl2

Which one of the following CORRECTLY illustrates the hybridization of orbitals of Be in the molecule BeCl2?

This item uses a figure in the original paper (not redrawn here).

  1. A. [image]
  2. B. [image]
  3. C. [image]
  4. D. [image]
Worked solutionUnofficial

No keyed letter is published for this item. No keyed letter is published for this 2017 E.C. natural item (Hybridization / BeCl2). All four choices are images (orbital diagrams). No answer on site. Be in BeCl2 is sp hybridized. A community comment suggests C.Try the options yourself, then practise the same subject timed in the app.

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2017 E.C. · natural · Q47 · Periodic table / classification

Scandium (Sc) has the electron configuration [Ar] 4s2^23d1^1. To which group of elements does it belong to?
  1. A. Transition elements
  2. B. Representative elements
  3. C. Nonmetals
  4. D. Inner transition elements
Worked solutionUnofficial

Answer: A

Answer A: Transition elements. The stem is: Scandium (Sc) has the electron configuration [Ar] 4s2^23d1^1. To which group of elements does it belong to? Letter A is the Abrari key for this Periodic table / classification.

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q71 · Atomic structure / subatomic particles

Which one of the following CORRECTLY shows the relative charges of an electron, proton and neutron, respectively?
  1. A. 0, -1, +1
  2. B. 0, +1, -1
  3. C. -1, 0, +1
  4. D. -1, +1, 0
Worked solutionUnofficial

Answer: D

Answer D: -1, +1, 0. The stem is: Which one of the following CORRECTLY shows the relative charges of an electron, proton and neutron, respectively? Letter D is the Abrari key for this Atomic structure / subatomic particles.

📖 G11 Chemistry, Unit 1, §1.3, p. 23“Isotopes of an element are atoms that have different numbers of neutrons and different mass numbers.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q72 · Atomic structure / Bohr model

Which statement below CORRECTLY describes the Bohr's model of an atom?
  1. A. Electrons and neutrons are found in the nucleus.
  2. B. Protons and electrons are found in the nucleus.
  3. C. Electrons move in circular orbits around the nucleus.
  4. D. Protons move in circular orbits around the nucleus.
Worked solutionUnofficial

Answer: C

Answer C: Electrons move in circular orbits around the nucleus.. The stem is: Which statement below CORRECTLY describes the Bohr's model of an atom? Letter C is the Abrari key for this Atomic structure / Bohr model.

📖 G11 Chemistry, Unit 1, §1.4, p. 36“The electron in an hydrogen atom travels around the nucleus in a circular orbit.”

Unofficial — solved by Abrari, not an official EAES key.

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2017 E.C. · natural · Q73 · Periodic table / periodicity

Which statement below CORRECTLY describes periodicity? Periodicity is
  1. A. a row in the Periodic Table which contains elements with same number of shells.
  2. B. a regular repetition of chemical and physical properties in the Periodic Table.
  3. C. a column in the Periodic Table which contains elements with similar chemical properties.
  4. D. a measure of electronegativity which runs from least electronegative to most electronegative elements.
Worked solutionUnofficial

Answer: B

Answer B: a regular repetition of chemical and physical properties in the Periodic Table.. The stem is: Which statement below CORRECTLY describes periodicity? Periodicity is Letter B is the Abrari key for this Periodic table / periodicity.

Unofficial — solved by Abrari, not an official EAES key.

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