(b) What are 'core electrons'?

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1. Core electrons are the electrons in an atom that are not involved in chemical bonding.
2. They are located in the inner shells of an atom, closer to the nucleus, and are not part of the valence shell.
3. Core electrons are typically more tightly bound to the nucleus compared to valence electrons.
4. In electron configuration, core electrons are represented by the filled inner orbitals, while valence electrons are in the outermost orbitals.
5. Understanding core electrons is important for explaining properties like atomic size, ionization energy, and shielding effect.

Key Concepts

Core Electrons

Core electrons are the electrons in an atom that are not involved in chemical bonding and are located in the inner shells, closest to the nucleus. They are typically shielded from the effects of external electric fields and do not participate in reactions, unlike valence electrons, which are found in the outermost shell and are responsible for an atom's chemical properties.

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's atomic orbitals. It is represented using a notation that indicates the energy levels and sublevels occupied by electrons. Understanding electron configuration is essential for identifying core and valence electrons, as it helps visualize which electrons are involved in bonding and which are core electrons.

Shielding Effect

The shielding effect refers to the phenomenon where inner electrons (core electrons) reduce the effective nuclear charge felt by outer electrons (valence electrons). This effect influences the chemical behavior of an atom, as it affects the attraction between the nucleus and the valence electrons, thereby impacting ionization energy and reactivity.