Which one among the following is responsible for determining the chemical properties of an element?

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CDS-II (General Knowledge) Official Paper (Held On: 01 Sept, 2024)
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  1. Protons
  2. Electrons
  3. Neutrons
  4. Nucleus

Answer (Detailed Solution Below)

Option 2 : Electrons
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The correct answer is  Electrons.

Key PointsDetermining Chemical Properties

  • Electrons are subatomic particles with a negative charge that orbit the nucleus of an atom.
  • The chemical properties of an element are primarily determined by the arrangement of its electrons, especially those in the outermost shell, also known as the valence shell.
  • Atoms with the same number of valence electrons often exhibit similar chemical behavior. For example, elements in the same group of the periodic table have similar valence electron configurations and thus similar chemical properties.
  • Electron configuration influences how atoms interact with each other, including how they form chemical bonds. For instance, atoms tend to gain, lose, or share electrons to achieve a full valence shell, leading to the formation of ionic or covalent bonds.
  • Protons and neutrons (which reside in the nucleus) determine the identity and mass of the element but do not directly influence its chemical properties.
  • The nucleus contains protons and neutrons and is positively charged, but it is the electrons that are involved in chemical reactions.
  • Hence, it is the electrons, particularly the valence electrons, that play a crucial role in determining the chemical properties of an element. Hence, statement 1 is correct.

Additional Information

  • Valence Electrons: These are the electrons in the outermost shell of an atom and are crucial for determining an element's chemical properties.
  • Periodic Table: Elements are arranged in the periodic table in a way that reflects their electron configurations. Elements in the same group have similar valence electron configurations and thus exhibit similar chemical properties.
  • Bond Formation: Atoms interact to form chemical bonds in order to achieve a stable electron configuration, often resembling the nearest noble gas configuration. This drive to achieve stability leads to the formation of ionic, covalent, or metallic bonds.
  • Reactivity: The reactivity of an element is influenced by the ease with which it can gain, lose, or share electrons. For example, alkali metals (Group 1) are highly reactive because they readily lose their single valence electron.
  • Ions and Isotopes: While ions are atoms that have gained or lost electrons and thus have a charge, isotopes are atoms of the same element with different numbers of neutrons. Isotopes have similar chemical properties because they have the same number of electrons.
  • Noble Gases: These elements have a full valence shell, making them largely inert and non-reactive under standard conditions.
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