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Exam Review

Key Facts: UEE Chemistry Exam

100 minutes

Exam Duration

EEC (eec.mn/post/6813)

44 (40 + 4)

Tasks

EEC 2026 blueprint and paper

200–800

Score Scale

EEC (eec.mn/en/?p=935)

5,800 MNT

Fee

EEC fee notice (2023)

UEE Chemistry is a 100-minute EEC paper with 44 tasks (40 five-option items plus 4 open problems worth 32 points); results are reported on a 200–800 scale. The 2026 weights are general chemistry 29.5%, physical 25%, organic 25% and inorganic 20.5%.

Sample UEE Chemistry Practice Questions

Try these sample questions to review concepts for the UEE Chemistry exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which of the following sets of quantum numbers (n, l, ml, ms) represents an allowed state for an electron in an atom?
A.n = 4, l = 0, ml = 0, ms = +1
B.n = 2, l = 2, ml = 0, ms = -1/2
C.n = 3, l = 1, ml = +2, ms = +1/2
D.n = 3, l = 2, ml = -1, ms = +1/2
Explanation: For an orbital quantum state, the principal quantum number n is a positive integer (n >= 1). The azimuthal quantum number l ranges from 0 to n - 1 (for n = 3, l can be 0, 1, or 2). The magnetic quantum number ml ranges from -l to +l (for l = 2, ml can be -2, -1, 0, +1, +2). The spin quantum number ms must be either +1/2 or -1/2. Therefore, n = 3, l = 2, ml = -1, ms = +1/2 is fully permitted.
2What is the ground-state electron configuration of a neutral copper atom (29Cu)?
A.[Ar] 3d¹⁰ 4s¹
B.[Ar] 3d⁹ 4s²
C.[Ar] 3d⁸ 4s² 4p¹
D.[Ar] 3d¹⁰ 4p¹
Explanation: Copper has an anomalous ground-state electron configuration due to the extra stability associated with a completely filled 3d subshell. An electron from the 4s orbital shifts to the 3d subshell, yielding [Ar] 3d¹⁰ 4s¹ instead of the naive Aufbau prediction [Ar] 3d⁹ 4s².
3Moving from left to right across Period 3 of the Periodic Table (from Na to Cl), how do atomic radius and first ionization energy typically change?
A.Both atomic radius and first ionization energy decrease
B.Atomic radius increases while first ionization energy decreases
C.Both atomic radius and first ionization energy increase
D.Atomic radius decreases while first ionization energy generally increases
Explanation: Across a period from left to right, nuclear charge (Z) increases while electrons are added to the same principal energy level with comparable shielding. The increasing effective nuclear charge (Zeff) pulls valence electrons closer to the nucleus, decreasing atomic radius and requiring more energy to remove an electron (increasing first ionization energy).
4Why does nitrogen (Z = 7) have a higher first ionization energy (1402 kJ/mol) than oxygen (Z = 8, 1314 kJ/mol), despite oxygen having a greater nuclear charge?
A.Nitrogen has a stable half-filled 2p³ subshell, whereas oxygen has paired electrons in a 2p orbital that experience inter-electronic repulsion
B.Oxygen has a larger atomic radius than nitrogen, making its outer electrons easier to remove
C.Nitrogen's 2p electrons provide greater core shielding than oxygen's 2p electrons
D.Oxygen's valence electrons occupy a higher principal energy level than nitrogen's valence electrons
Explanation: Nitrogen has a 2s² 2p³ valence configuration where each of the three 2p orbitals contains a single electron with parallel spins, imparting exchange energy stability. Oxygen has a 2s² 2p⁴ configuration containing one doubly occupied 2p orbital. The electrostatic repulsion between the two paired electrons in that orbital makes removing one electron easier, lowering oxygen's first ionization energy below that of nitrogen.
5An ion contains 35 protons, 45 neutrons, and 36 electrons. What is the correct isotopic representation for this species?
A.⁸⁰₃₅Br⁻
B.⁸⁰₃₅Br⁺
C.⁷⁰₃₅Br⁻
D.⁸⁰₄₅Rh⁻
Explanation: The atomic number Z equals the number of protons (35), identifying bromine (Br). The mass number A equals protons + neutrons = 35 + 45 = 80. With 36 electrons and 35 protons, there is one excess negative charge (-1). Thus, the correct symbol is ⁸⁰₃₅Br⁻.
6What is the ground-state electron configuration of the iron(III) cation, Fe³⁺ (atomic number Z = 26)?
A.[Ar] 3d⁵
B.[Ar] 3d³ 4s²
C.[Ar] 3d⁶
D.[Ar] 3d⁴ 4s¹
Explanation: Neutral iron has the configuration [Ar] 3d⁶ 4s². During ionization of transition metals, electrons in the outermost 4s subshell are lost before 3d electrons. Forming Fe³⁺ requires removing three electrons: two from 4s and one from 3d, leaving [Ar] 3d⁵.
7Which of the following elements has the highest electronegativity value on the Pauling scale?
A.Nitrogen (N)
B.Chlorine (Cl)
C.Oxygen (O)
D.Fluorine (F)
Explanation: Fluorine is the most electronegative element in the Periodic Table, with a Pauling electronegativity value of approximately 3.98 (commonly rounded to 4.0). Its small atomic radius and high effective nuclear charge give it the strongest tendency to attract bonding electron pairs.
8Which of the following isoelectronic ions has the largest ionic radius: N³⁻, O²⁻, F⁻, or Na⁺?
A.N³⁻
B.Na⁺
C.F⁻
D.O²⁻
Explanation: All four ions are isoelectronic, possessing 10 electrons with the neon configuration 1s² 2s² 2p⁶. Within an isoelectronic series, radius decreases as nuclear charge increases. N³⁻ has the lowest nuclear charge (Z = 7 protons), so its electrons experience the weakest inward electrostatic pull, resulting in the largest ionic radius.
9Calculate the wavelength of the photon emitted during an electronic transition from n = 4 to n = 2 in a hydrogen atom (Rydberg constant R_H = 1.097 × 10⁷ m⁻¹).
A.486 nm
B.656 nm
C.434 nm
D.410 nm
Explanation: The Rydberg formula gives 1/λ = R_H * (1/n₁² - 1/n₂²) = 1.097 × 10⁷ m⁻¹ * (1/4 - 1/16) = 1.097 × 10⁷ * (3/16) = 2.0569 × 10⁶ m⁻¹. Inverting gives λ = 1 / (2.0569 × 10⁶ m⁻¹) = 4.862 × 10⁻⁷ m = 486 nm (the H-beta line of the Balmer series).
10How many unpaired electrons are present in the ground state of an isolated phosphorus atom (Z = 15)?
A.3
B.1
C.2
D.5
Explanation: The electron configuration of phosphorus is [Ne] 3s² 3p³. According to Hund's rule of maximum multiplicity, electrons occupy degenerate 3p orbitals singly with parallel spins before pairing up. Therefore, the 3p subshell contains three unpaired electrons (3px¹ 3py¹ 3pz¹).

About the UEE Chemistry Exam

The chemistry paper of Mongolia's national university entrance examination (Элсэлтийн шалгалт, ЭШ; formerly ЭЕШ) is set by the Education Evaluation Center and written in Mongolian. OpenExamPrep offers 100 free English-language practice questions across general, physical, inorganic and organic chemistry, with worked calculations and explanations for every option. The bank is an English-language multiple-choice study adaptation, not an official translation or a simulation of the paper's five-option and open-response format.

Exam sponsor: Education Evaluation Center (Боловсролын үнэлгээний төв, БҮТ / EEC). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Part 1 (68 points): 40 five-option selection items. Part 2 (32 points): 4 multi-step open-response problems. Scores are converted to the 200–800 scale.

Time Limit

100 minutes

Passing Score

No pass mark; results on a 200–800 scale, with university and program threshold scores (босго оноо)

Exam / Certification Fees

5,800 MNT per subject (EEC 2023 fee notice)

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

29.5%

General chemistry

Atomic structure, periodic trends, bonding, the mole and stoichiometry.

25%

Physical chemistry

Thermochemistry, kinetics, equilibrium, solutions, pH and electrochemistry.

20.5%

Inorganic chemistry

Metals, non-metals and their compounds.

25%

Organic chemistry

Hydrocarbons, functional groups, isomerism, reactions and biomolecules.

Preparing for the UEE Chemistry Exam

What You Need to Know

  • Passing score: No pass mark; results on a 200–800 scale, with university and program threshold scores (босго оноо)
  • Assessment: Part 1 (68 points): 40 five-option selection items. Part 2 (32 points): 4 multi-step open-response problems. Scores are converted to the 200–800 scale.
  • Time limit: 100 minutes
  • Exam / certification fees: 5,800 MNT per subject (EEC 2023 fee notice) Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

UEE Chemistry: Suggested Study Strategy

1Part 2 is worth 32 points, so practice multi-step calculations (stoichiometry, yield, concentration, pH) without answer options.
2Balance equations and check units before calculating; many wrong options come from unbalanced coefficients.
3Learn periodic trends and bonding thoroughly, since general chemistry is the largest unit (29.5%).
4Make a table of organic functional groups with their typical reactions and tests.
5Time yourself: 44 tasks in 100 minutes, with the open problems taking the most time.

Frequently Asked Questions

What is the Mongolia UEE chemistry examination?

It is the chemistry subject of Mongolia's national university entrance examination (Элсэлтийн шалгалт, ЭШ; formerly ЭЕШ), set by the Education Evaluation Center (EEC) and written in Mongolian. Medicine, pharmacy, chemical engineering and other science programs use it for admission.

How is the 2026 chemistry paper structured?

It lasts 100 minutes and has 44 tasks worth 100 points: 40 five-option selection items in Part 1 (68 points) and 4 open-response problems in Part 2 (32 points).

What score do I need?

There is no pass mark. Scores are standardized to a 200–800 scale with a mean of 500, and each university and program sets its own minimum threshold score (босго оноо).

How much does the exam cost?

EEC's most recent published fee notice (2023) sets the fee at 5,800 MNT per subject. We did not find a separate 2026 fee notice, so check the registration portal when you register.

Why is this bank in English if the exam is in Mongolian?

OpenExamPrep publishes one English-language bank per exam. It is an independent MCQ study adaptation of the published specification, not an official translation, and it uses four options instead of the official five. Practice with EEC's Mongolian-language past papers as well.