9. Sınıf Kimya 1. Dönem 1. Yazılı Soruları ve Çözümleri | OYSS Senaryo 5 (Maarif Modeli)

Summary

The video works through seven sample questions for a 9th-grade chemistry exam using OYSS Scenario 5. The instructor notes that the same learning outcomes appear across different scenarios, so students should practise questions from the other scenarios as well.

1. Battery Materials and Practical Usefulness

Two rechargeable batteries began with equal capacity and were tested under the same conditions for 150 charging cycles. One retained 88% of its initial capacity, while the other retained 63%.

The instructor concludes that electrode material matters: the battery retaining more capacity is more durable and performs better over time, even if both batteries still operate. Better battery materials could help devices such as phones and vehicles run longer between charges, improving everyday convenience.

2. Laboratory Safety and Chemical Purity

Two actions in the described procedure could contaminate chemicals:

• Using the same spatula for two substances without cleaning it: Material from the first container can be transferred to the second.
• Returning excess material to its original stock container: If the material has become contaminated, it can contaminate the entire stock.

To preserve purity, clean or replace equipment between substances, and do not return used or potentially contaminated material to a stock container. Contamination can change a substance’s properties and affect the intended experiment.

3. Subatomic Particles and Electrical Behavior

In an electric field, negatively and positively charged particles deflect in opposite directions, while an uncharged particle does not deflect.

A lack of deflection does not mean the particle does not exist. A neutron has no electric charge, but it does have mass and contributes to an atom’s mass. Uncharged particles are harder to detect using methods based only on electrical or magnetic interactions.

The delayed identification of the neutron illustrates how limitations in experimental methods can affect scientific understanding—and how new evidence and technology can change it.

4. Dalton’s Atomic Theory and Isotopes

The example compares neutral atoms with the same number of protons but different numbers of neutrons. Atoms of the same element can therefore have different masses, contradicting Dalton’s claim that all atoms of an element have the same mass.

The instructor uses this example to illustrate that scientific theories may be revised when new evidence becomes available.

5. Orbital Shapes, Orientation, and Energy

Orbitals with the same shape do not necessarily have the same energy: the 1s and 2s orbitals are both spherical but have different relative energies.

Orbitals with different spatial orientations can have equal energy: 2pₓ and 2pᵧ point in different directions but have the same relative energy in the example.

The key lesson is to distinguish orbital shape, orientation, and energy; shape alone does not determine energy.

6. Relative Orbital Energies and the Aufbau Order

The comparisons give this order, from lower to higher energy:

3s < 3p < 4s < 3d < 4p

The instructor emphasizes that the principal energy level alone does not determine an orbital’s energy. Thus, 3d is not automatically lower in energy than 4s just because it belongs to the third principal level.

Students are encouraged to learn the filling sequence, including:

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p

The instructor also recalls that orbital types begin at different principal levels: s at 1, p at 2, d at 3, and f at 4.

7. Electron Configuration and the Orbital-Filling Rules

The example atom’s configuration is 1s² 2s² 2p⁶ 3s² 3p⁴. Counting the electrons gives 16. Because the atom is neutral, it also has 16 protons, so its atomic number is 16.

The instructor reviews three rules:

• Aufbau principle: Electrons fill lower-energy orbitals before higher-energy ones.
• Pauli exclusion principle: An orbital holds at most two electrons, and they must have opposite spins.
• Hund’s rule: Electrons fill orbitals of equal energy singly, with parallel spins, before pairing.

In the 3p⁴ arrangement, the three equivalent p orbitals each receive one electron before the fourth electron pairs in one of them.

Study Advice

• Practise questions resembling the activities and end-of-chapter questions in Ministry of Education textbooks.
• Pay particular attention to orbital energy comparisons and the Aufbau, Pauli, and Hund rules.
• Solve many practice questions and compare your answers with the reasoning each question requires.

Speakers and Sources Featured

• Presenter: A chemistry instructor explains the questions throughout. The subtitles do not state the presenter’s name; the channel metadata identifies the channel as Levent Özdede ile Kimya.
• Sources and references mentioned: OYSS Scenario 5; Ministry of Education chemistry textbooks and prior-year written-exam questions.
• The video refers to hypothetical students’ claims as part of the exercises, but no separate student speaker is identifiable in the subtitles.