2.25. Atomic Structure: Law of conservation of energy

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2.25. Atomic Structure: Law of Conservation of Energy

Understanding the atomic structure and the Law of Conservation of Energy is a fundamental aspect for the study of Chemistry, especially for those preparing for the National High School Exam (ENEM). This chapter of our Chemistry e-book course will cover these concepts in a detailed and accessible way.

Understanding Atomic Structure

An atom is the smallest particle of a chemical element that still retains the properties of that element. It is composed of three main subatomic particles: protons, neutrons and electrons. Protons and neutrons make up the nucleus of the atom, while electrons orbit the nucleus at specific energy levels.

Protons have a positive charge, neutrons have no charge (they are neutral), and electrons have a negative charge. The number of protons in an atom determines the atomic number of the element, while the total number of protons and neutrons determines the atomic mass.

Law of Conservation of Energy

The Law of Conservation of Energy is a fundamental principle in physics and chemistry. It states that energy cannot be created or destroyed, only transferred or transformed. This means that the total amount of energy in a closed system remains constant regardless of changes that occur within the system.

In chemistry, this law is often applied to the study of chemical reactions. For example, in an exothermic reaction, energy is released as heat. While it may appear that energy has been "lost", it has actually been transferred from the chemical system to the environment. Likewise, in an endothermic reaction, energy is absorbed from the environment into the chemical system. In both cases, the total amount of energy remains the same.

Atomic Structure and Conservation of Energy

Understanding atomic structure and the Law of Conservation of Energy is crucial to understanding how chemical reactions occur. In a chemical reaction, atoms are rearranged to form new substances. During this process, electrons can be transferred from one atom to another or shared between atoms.

These transfers and sharing of electrons involve changes in energy. For example, when an electron is transferred from one atom to another, it must absorb energy to move to a higher energy level, and then release that energy when it falls back to a lower energy level.

According to the Law of Conservation of Energy, the total energy involved in these electron transfers must remain constant. This means that the energy absorbed by the electron when moving to a higher energy level must be equal to the energy released when it falls to a lower energy level.

In summary, atomic structure and the Law of Conservation of Energy play a key role in our understanding of chemical reactions. By understanding these concepts, you will be well prepared to answer chemistry-related questions on the ENEM and other exams.

Conclusion

Atomic structure and the Law of Conservation of Energy are fundamental concepts in chemistry, and their understanding is crucial for preparing for ENEM. We hope this chapter has helped clarify these concepts and prepare you for exam success.

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283. Periodic Classification of Elements